Tourists walk into the Stonewall in Greenwich Village--the descendent of many decades of clandestine gay bars and ground zero of the gay-liberation movement--to find a snug little hole in the brick wall. It's as if this symbol of affectional freedom among men feels like the closet, expanded. Similarly, most gay bars in our neck of the prairie still seem like secret clubhouses, retaining all the darkness and insularity of a Prohibition-era speakeasy. This is why the bright new boy on the block, Boom, is so refreshing. Bathed in sunshine through its glass front until the sun goes down, the admittedly trendy little spot matches blond brick with blond wood--plus a blond model in the wall mural, which looks like a billboard advertisement for how handsomely the Norwest building reflects in the IDS Tower--très moderne! The well-lighted walls are lined with flat "I have to admit it's getting better" television sets pumping a private video feed of 2001 disco hits. On Sundays at about 6:00 p.m., the AV fare switches to musical numbers, which are vee-jayed through a glass window from above by some anonymous Oz generous enough to accept written requests via the waitstaff. Within minutes the impeccably groomed guppie clientele is singing along to Michael Jackson in The Wiz, Donald O'Connor in Singin' in the Rain, and the troubled preteens of South Park. The scene could almost be a timid newcomer's vision of the perfect gay initiation: Polite fun with plenty of maneuvering room. Sit in the discreetly spaced, ass-molded, and surprisingly comfortable metal bar stools (encore, très moderne!) and take in the huge interior, with its high, molded-metal ceiling and living plants on the floor. Note that both the ostrich fillet ($16.95 from the adjoining restaurant, Oddfellows) and the men (women seem to disappear when musicals come on) are dressed better than you are. But they can't sing any better than you can.