Nicole Richie has been ruling the scene Tuesdays at L.A. club Guy’s hot new karaoke night. Recently, Richie and pal Lindsay Lohan hit the stage for Dr. Dre and Eminem’s “Forget About Dre.” “Just so you know, I’m black, so this is from my roots!” Richie yelled into her microphone. And when they poured their hearts out to the Journey classic “Don’t Stop Believin,’” Mary-Kate Olsen, who sat nearby, held up a lighter concert-style. “They gave it their all and had a great time,” says a clubgoer. I knew she was a girl after my own heart. Except for the heroin thing. And the underwear-over-the-jeans thing. Looks like she's making good money karaoking.