DRIVE UP the Baltimore-Washington Parkway at dusk and, just when you hit Route 175, it looms on the right, a massive neon sign announcing "MAX BLOB'S PARK." Max Blob's Park? A sci-fi amusement park, perhaps, stuffed with protoplasmic wonders? A fat man's paradise of cream puffs, fudge and oversized easy chairs?

Guess again.

Blob's Park is this area's preeminent polka palace, a mammoth barn of a place where the lager flows and the dancing never stops. Since 1933, when German emigr,e Maximilian Blob built a small bowling-alley-cum-social-club on the grounds of his farm in Jessup, Maryland, the Blob family has provided music, mirth and knockwurst to all who seek such things. Over the years, the building has been enlarged to accommodate wave after wave of foot-stomping patrons; the current facility, a kitsch marvel, holds up to a thousand people.

Pay a measly $2 cover charge, and soon you're awash in the sounds of The Rheinlanders, a five-member band (accordion, electric guitar, drums, trumpet and sax) that veers from the "Beer Barrel Polka" to "New York, New York" to a seductive rhumba and then back to polka again. The huge wooden dance floor is plastered with dancers: middle-aged women in cocktail dresses, bearded guys in jeans and suspenders, paunchy old geezers with impeccable timing, little kids twirling away with their older siblings. Lines form, and the "Alley Cat" starts up. The bandleader calls "Chicken Dance!" and hundreds of sweaty bodies face the musicians, listen for cues, and launch into a group spectacle of waving hands, flapping arms, gyrating hips. Miss a step, or bump into the energetic couple beside you, and nobody says boo. That's the beauty of Blob's Park.

If you're the sedentary type, find a seat at one of the zillion or so long communal tables surrounding the dance floor. Soon a folksily garbed waitress will appear, rolling a cart laden with black forest cake, cheesecake and other desserts, or immense sausage and cheese platters. Eat hearty, and then take a stroll along the periphery. Check out the beer stein collection, the plastic shark hung over the painting of the Madonna, the flags of all nations, the photograph of the Blob's Park soccer team (circa ?) or the blowup of the late Herr Max himself. Mingle with the boys over at the bar, where you can order a Rumple minze (one of eight German liqueurs available) and watch the tube. Blob's has something for everyone.

FASHING EXPEDITION -- If you're up for a wild evening this Friday night, pull on your lederhosen and hurry over to Blob's annual Fashing celebration, the German equivalent of Mardi Gras. Bavarian dancers will perform, and prizes will be awarded for best costumes.

MAX BLOB'S PARK -- From the Beltway, take the Baltimore-Washington Parkway north to Route 175 east toward Odenton, veer right past the firehouse and down Blob's Park Road. Open Friday and Saturday from 7:30 p.m. to 1 a.m.; Sunday from 3 to 10. Big band night on the first Wednesday of every month. 301/799-0155.