You know that moment when you're listening to a DJ, you hear the bass line creeping up and you're like, oh shit, here we go? Spastic geek Gregg Gillis, aka Girl Talk, lives in that transitory moment 100 percent of the time. One of the fastest-shifting, most interesting, and most fun cutters still working in the mashup biz--admittedly there aren't many of 'em--he's one of a few people who can make playing the computer look like fun. Onstage he strips down to his skivvies and jumps around like a white boy with his head cut off, and though his feet never seem to stay on the ground, somehow he keeps both hands on the table. And he uses the laptop like a real instrument, scrapping together all his pilfered samples on the fly, giving music nerds little boners because they can play that game where they keep track of how many different artists they can name in every song. CX Kidtronik and C-Mass open. Sat 9/9, 10 PM, Empty Bottle, 1035 N. Western, 773-276-3600 or 866-468-3401, $8.