Far too often, artists adopt a nickname and then forget what their moniker was supposed to mean. Not so with the St. Louis rap group Family Affair: the aptly named emcees are identical twin brothers. The pair has grand plans to kick it with kin on Friday, when it will celebrate turning 21 with a special performance at the Gramophone. "It's going to be a true family affair," says QB, who is two minutes younger than his brother, Rep. "We're going to have the whole nine, a big birthday cake and the whole family — you know, my momma's gonna be there and the old dude, too. Everybody except the kids, 'cause it's 21 and over." Rockwell Knuckles, Gotta Be Karim, Potzee and Youvee are also scheduled to appear.