Undoubtedly, Europe's best known fall festival is Oktoberfest, Bavaria's harvest frolic of gaily decorated brewery tents, brassy oom-pah-pah bands and polka dancers, of feasting and imbibing. But it is only one event in a calendar full of festivals celebrating, it seems, almost everything pleasurable.

For the Irish men and women of Galway, that bustling seaport on the Lough Corrib, late September means the celebration of the oyster. In Dijon, the home of France's famed Grey Poupon mustard since 1777, the first 12 days of every November are dedicated to the Gastronomics Fair in tribute to good food.

Some of Europe's festivals are glitzy international affairs of the arts; many are peculiar colloquialisms arising from centuries of tradition -- in food, religion or sport. Some are well mannered; others rowdy. Most warmly embrace outsiders.

Here's a sampling of festivals scheduled for late summer and fall in Europe, all of them worthy of planning a detour: Historical

France: the Day of the Fifes, August. Little Ribeauville' in Alsace, a French town noted for its gewu rtztraminer and riesling wines, holds a comely town party the last Sunday of every August -- the Day of the Fifes. Townspeople dress in traditional costumes as the village erupts into folk dancing and historic parade and vin ordinaire flows freely from a fountain in the town square.

Yugoslavia: September. Throughout the month, Moreska sword dancers perform high-speed synchronized steps with 16th-century weapons in the old fortress on the island of Korcula. The island best known as the birthplace of Marco Polo is a short hop across the channel from Orebic on the Peljesac Peninsula and offers pebble beaches and a cathedral displaying works by the 16th-century Venetian painter Tintoretto as the festival's fringe benefits.

Spain: Festival of the Virgen del Pilar, Oct. 8-16. Zaragoza, on the banks of Spain's Ebro River halfway between Madrid and Barcelona, is the site of this festival; legend holds that a vision of the Virgin Mary appeared to St. James on a column of an ancient Roman temple there. Women dressed in regional costume make floral offerings at the monumental Basilica del Pilar as the city of a half million swells into continuous folklore parades, music, feasting and the colorful jota, Aragon's colorful dance.

Turkey: Oct. 29. Every year, Turks take to torchlight processions, folk dancing and fireworks on the anniversary of the proclamation of the Turkish Republic 64 years ago.

Great Britain: Guy Fawkes Day, Nov. 5. Throughout Great Britain, this fireworks blowout commemorates the foiling of the 1605 plot to blow up Parliament and King James I.

Germany: Berlin's anniversary, through the end of the year. Among the major yearlong commemorative festivals winding down this fall is Berlin's celebration of its 750th anniversary. Founded in 1237, the divided city is sponsoring exhibitions, concerts, parades, street fairs and other events signifying Berlin's importance in European history and culture. In addition, the annual Berliner Festwochen, held from early September to Oct. 4, promises to be even spiffier this year, as it coincides with the birthday party. Always eclectic with chamber music, theater, dance and even circus performances, this year it will be heavy on the orchestral, with the Berlin Philharmonic emphasizing German composers.

Arts and Culture

Scotland: the Edinburgh Festival, Aug. 9-31. "The grande dame of festivals" fills this medieval capital's every nook with activities for three weeks every summer.The cultural schedule is long and crowded, from the first day's pageantry to the military tattooists at Edinburgh Castle to impromptu recitals along the Firth of Forth to offbeat shows in the ancient alleyways. Featured this year will be arts and performing artists of the Soviet Union and tributes to American composer George Gershwin on the 50th anniversary of his death. Switzerland: International Festival of Music, Aug. 15-Sept. 9. This festival in Lucerne is the season's last chance to tune into one of the biggest and most prestigious of Europe's classical music events of the year. Most of the major classical sprees take place in the summer when Europe's opera and orchestral "houses" are offseason and their stars available for guest appearances.

But unlike the sparkle and glitz that pervades Salzburg a month earlier (with ticket requests outnumbering available spaces four-to-one), Lucerne's is a bit more accessible. Although the atmosphere at each evening concert is black-tie, top opera tickets at Lucerne cost $70 compared with $240 at Salzburg. The range on stage this year: five performances of Arthur Miller's "Death of a Salesman" in German, plus Mahler, Mozart, Chopin and Brahms.

Montreux-Vevey Festival of Music, Aug. 25-Oct. 3. In the shadow of the distant Alps, the schedule for this year's elegant festival includes performances by Pinchas Zukerman, Zubin Mehta and the Israel Philharmonic Orchestra, Yo-Yo Ma and, on its final date, pianist Ljubov Timofeeva and the Orchestre Symphonique d'Etat de l'URSS, playing Tchaikovsky, Evgeni Svetlanov conducting.

Finland: the Helsinki Festival, Aug. 27-Sept. 9. Along with the seasonal return of the university students and Finns from their country cottages, this festival is like a wake-up call arousing that neoclassical city by the sea from its summer slumber. It attracts leading international and Finnish artists of film, canvas, stage, dance and music. Concerts are held in the grand white "house" on the lake, Finlandia Hall, or for smaller performances in the Rock Church, named for the granite it's built into and not the style of music performed. Among the featured artists this year will be conductor Riccardo Muti and the Philadelphia Orchestra and the Paul Taylor Dance Company.

The Dublin Theatre Festival, Sept. 28-Oct. 11. Celebrating its 29th year of premiering famous plays and playwrights, this festival -- with new productions opening daily -- satisfies almost any theater taste, comedy to experimental, classics to new works, most by Irish writers.

Ireland: the Belfast Festival of the Arts, Nov. 10-28. In Ireland, there are plenty of festivals year-round, many so small you'll never hear of them until you're there. But they take on a particular glow: Irish licensing laws that generally shut pub doors by 11 p.m. are considerably more flexible during the festivals, allowing locals to drink a stout till 1 a.m. and forget about "the troubles." Every November for 25 years, the Belfast Festival of the Arts has helped forget about the troubles, too. One of the largest festivals in Britain and Ireland, it presents a wide range of artistic media around the cloisters of Queens University, from opera to performances by the Royal Shakespeare Company to jazz and an occasional Irish jig.

The Netherlands: through the end of the year. Amsterdam's designation by the European Economic Community as the "Cultural Capital of Europe '87" means that Dutch city is hosting some of Europe's leading artists and contemporary talents in music and the arts. Fall highlights include the Bolshoi Ballet performances of "Raymonde" and "The Golden Age," a mid-October Jazz Festival, a major exhibition in the Rijksmuseum called "Netherlands: Landscapes by 17th Century Dutch Masters," a season-long run of the play "Cats" and, Sept. 10-22, "Cinema Europe 1987," featuring the top-40 postwar European films.

Wine and Food

Greece: Athens wine festival, through mid-September. Unlimited access to barrels of wine produced throughout Greece, snacks of souvlaki and barbecued chicken, traditional Greek bands and group dancing that lasts into the night. Cyprus: The Limassol Wine Festival, Sept. 2 to 13. More than 100,000 visitors a year feast, sing, dance 'and sample the new wine. An entrance fee of less than a dollar gets a glass and entrance to the pavilions of Limossol's four major wineries. Outdoor restaurants serve traditional Cypriot cuisine of roast pig, fish and grilled quail on a stick, stuffed grape leaves and sausages. And there are nightly shows of Cypriot folk dancing, ballad style and the colorful "crush" dance that signifies the stomping of the grapes. Germany: the Du rkheim Sausage Market and Wine Festival, Sept. 11-15 and 18-21. This festival in the Rhineland city of Bad Du rkheim is the largest of the German wine regalias, focusing on food, wine and what the Germans call "fun fairs," where streets are extravagantly decorated. Luxembourg: the Grevenmacher Grape and Wine Festival, Sept. 13-14. New Moselle wines flow at this town on Luxembourg's German border. Parades, floats and fireworks take over the streets surrounding the 13th-century castle and ruins as celebrants stop at one wine-sampling pavilion after another. France: Les Trois Glorieuses, November. This event, the third weekend of November, marks Europe's most famous of wine-worshiping festivals. Bidding on Burgundy's new wines during the hectic and exciting "Three Days of Glory" at the Hospices of Beaune serves as a barometer of price on each year's vintage and has repercussions on the wine market worldwide.

But the third weekend of November in Beaune isn't just business. It is a marathon feast -- three days of brass bands, trumpeters in medieval costumes, grand-scale banqueting and wine tasting that attracts international wine connoisseurs and celebrated guests to the nearby chateaus of a town that for centuries has done practically nothing more than produce fine wine. Reservations must be made far -- as much as a year or more -- in advance.

Sports

Italy: the Regatta of Venice, Sept. 3. Two-oared gondolas compete in this event, marked by a parade of ceremonial boats and, on shore, Venetian celebration. Switzerland: The Unspunnen Wrestling Festival, Sept. 6. In Interlaken, this is an Alpine wrestling event that attracts the fittest of the mountain locals to compete in an atmosphere of rivalry and revelry. Increasingly a tourist attraction, town folks dress in traditional garb, and food and drink native to the Swiss Alps is everywhere. Temperatures are cool at this all-outdoor event that, according to the Swiss tourist office, even invites an occasional "fit" visitor to enter the fray. The competition finishes up with the throwing of the 185-pound Unspunnen stone. Cyprus: the Cyprus Road Rally, Sept. 25-27. The entire island of Cyprus focuses on one of the toughest of the European road races that starts in Nicosia and ends 840 miles later in Paphos. Portugal: the San Martinho Fair, Nov. 8-9. Fanciers of fine Portuguese-bred stallions stampede this event in Golega to bid on horses, but the attractions for most travelers are the cowboys showing off their horsemanship, the bullfights, folk dancing, food and fireworks.

Oddities

Ireland: the Rose of Tralee International Festival, Aug. 21-28. In Ireland's County Kerry, the "Rose" of the song comes to life in a week of Irish cabarets, dog-racing, brass bands, dances and performances of traditional Irish music, culminating in the annual selection of the new "rose" from among the young women who come from around the world with hopes of taking home the traditional Waterford crystal trophy and the title "the Rose of Tralee." France: the Fe~te de l'Humanite', September. Held annually during the second week of September in Paris, this wingding is hosted by the French Communist Party, but most visitors go to sample not ideology but a wonderful diversity of native food and drink sold by Communist Party members from around the world. The Netherlands: the Delft Old Art and Antiques Fair, Sept. 10-22. This is one of Europe's most prestigious shows of venerable art and top-quality furnishings. Denmark: Tivoli Gardens' closing day for the season, Sept. 15. Copenhagen's legendary park and amusement center is illuminated after dark by more than 100,000 colored lights. Spain: the Saffron Rose Festival, Oct. 25. In the Consuegra region around Toledo, Spaniards celebrate the harvesting of the expensive spice that characterizes so many of the culinary dishes from the area. Switzerland: the Zibelemaerit, Nov. 23. The traditional Swiss onion market in Switzerland's capital city of Bern. As early as 5 a.m., Swiss farmers cart their onions to the market; also displayed will be decorated onions, painted onions, onion craftwork.