Outdoor Film Festival

"Raiders of the Lost Ark," "Casablanca" and other film classics will be shown on a giant outdoor screen at the free Cable TV Montgomery/NIH outdoor film festival, Friday through Aug. 22 on the grounds of the National Institutes of Health, 9000 Rockville Pike (Metro: Medical Center). The grounds open at 7; the films start at dusk. The schedule: "Raiders of the Lost Ark," Friday; "Rocky," Saturday; "West Side Story," Sunday; "Willy Wonka & the Chocolate Factory," Monday; "When Harry Met Sally," Tuesday; "Casablanca," Wednesday; "Singin' in the Rain," Thursday; "Field of Dreams," Aug. 20; "Titanic" Aug. 21 (because of its length, "Titanic" starts at 8); and "The Rugrats Movie," Aug. 22. Food and desserts from area restaurants will be sold, starting at 7. Proceeds benefit NIH charities. Call 301/881-0143.

Premier Pens

The eighth annual Washington DC Pen Supershow features pens old and new, some worth only a few dollars and others worth several thousand. Exhibitors from all over the United States, Europe, Latin America, Africa and Asia will be on hand, buying, selling and trading. The show will be held Saturday and Sunday from 10 to 5 at the Ritz Carlton Hotel, Tysons II Mall, 1700 Tysons Blvd., McLean. Admission is $5; children under 12 admitted free. Call 703/506-4300.

A Ball at the Mall

A weekend's worth of festivities will mark the grand opening of the Dulles Town Center. Activities include a free concert Friday at 6:30 p.m. with Jr. Cline and the Recliners plus a hot air balloon glow at 8. Olympic figure skater Michael Weiss leads a parade Saturday at 10 a.m. Family Fun Day is Sunday beginning at noon and includes appearances by DC United's Roy Lassiter and Geoff Aunger from 12:30 to 2:30. The 130-store mall is at Routes 7 and 28 in Dulles. Call 703/404-7100.

Opera at Wolf Trap

The Wolf Trap Opera Company presents Mozart's "Die Zauberflute" ("The Magic Flute"), in German with English supertitles, Thursday and Aug. 21 at 8 at Wolf Trap Park's Filene Center, 1551 Trap Rd., Vienna. Tickets for Thursday's performance cost $29 to $45 in-house, $17 on the lawn; on Aug. 21, they are $32 to $48 in-house, $19 lawn. For tickets, call ProTix, 703/218-6500 (service charges). For information, call 703/255-1860.

Kunta Kinte Festival

African dance, Caribbean, R&B and gospel concerts; hands-on crafts and mask workshops; storytellers and a crafts marketplace are showcased at the Kunta Kinte Heritage Festival, Saturday from 10 to 8 and Sunday from 10 to 6 at St. John's College, 60 College Ave. in Annapolis. Admission is $5, $3 for seniors and children 4 through 12 (younger free). From the Capital Beltway, take U.S. 50 east to the Rowe Boulevard exit, continue to the third traffic light, turn left into the parking lot and then make a left to the lower lot. Call 410/349-0338.

Agassi Takes Court

Andre Agassi, winner of the French Open and Wimbledon finalist, leads the field of 56 of the world's top professional tennis players in the Legg Mason Tennis Classic, opening Saturday and running through Aug. 22 at the William H.G. Fitzgerald Tennis Center at 16th and Murrow streets NW. Qualifying matches are Saturday and Sunday at 4. Main draw singles play starts Monday at 4 and continues through Thursday. Quarterfinal matches are Aug. 20 at noon and 7; semifinals are Aug. 21 at 1 and 7, with the final at 4 on Aug. 22. Tickets are $6 (for qualifying matches on first weekend) to $35. For information, call the tournament hot line, 202/ 721-9500; for tickets, call Ticketmaster, 202/432-7328.

Fair Season

The Prince William County Fair, perhaps the best fair value in the metropolitan area, opens its nine-day run Friday at noon and offers midway rides, demolition derbies, concerts and hundreds of exhibits. The fair runs through Aug. 21, from noon to 10 (midnight if the crowds are large). The midway opens at 2 and remains open until two hours after the gates close. The admission price includes carnival rides, grandstand entertainment, parking and exhibits. Admission is $10 for ages 7 through 59, $4 for seniors and children ages 3 through 6 (younger free). Take I-66 west to Route 234/Manassas south and drive seven miles to the fairground. Call 703/368-0173.

The Montgomery County Fair, which opens Friday and runs through Aug. 21, offers tractor pulls, horse shows, concerts and more. The fair opens with a `pre-fair" phase, which offers carnival rides and entertainment. The pre-fair is Friday from 3 to midnight and Saturday from 8 a.m. to midnight. The whole fair is open Sunday through Aug. 21 from 8 a.m. to midnight. The midway is open Friday from 3 to midnight, Saturday through Aug. 21 from 10 a.m. to midnight. Admission is $3 Friday and Saturday, $5 Sunday through Aug. 21 (seniors free on Tuesday until 4); ages 11 and younger free anytime). Free shuttles will operate from the Lakeforest Mall lots between 8 a.m. and midnight daily. Shuttles will also run between the Shady Grove Metro and the fair from 3 to midnight; round-trip fare is $2 (ages 11 and younger free). The fairground is on Perry Parkway, off Route 355 in Gaithersburg. Call 301/963-3247.

The small Worcester County Fair runs Friday through Sunday and is an inexpensive diversion for sun-worshipers weary of the Maryland beaches, only 20 miles away. The fair is open Friday from noon to 9, Saturday from 10 to 8 and Sunday from 10 to 4. Admission is $3, free for children high school age and younger with an adult. The fair is at the Furnace Town Historic Site, on Route 12 in Snow Hill, Md. Call 410/632-2032 or 410/632-1972.