If you're the kind of girl who likes to shriek "woo!" a lot, enjoys hearing Billy Joel songs played by dueling pianists and is looking for one last hurrah before getting married, make a date for the Barrel Room (105 NW 3rd Ave., 242-0700) next Saturday night. Get plastered on JELL-O shooters and fruity cocktails in plastic mugs ($6-$12), then hand the two live pianists $20 to play your favorite song, make racist jokes and call you a slut. Look, it's not my idea of a good time, but the woo girls love it and the place is packed wall to wall every weekend with people singing and dirty-dancing along to slightly out-of-tune covers of "Summer of '69" and "Livin' on a Prayer." And if slurping drinks through a penis-shaped straw while performers encourage you to flash your breasts at the crowd is how you want to spend your final night as a single lady, all I can say is: woooooo!