Like polyphonic ringtones, mashups are the real underground music. Any DJ who’s able to lay, say, Christina Aguilera’s vocals over a Scorpions song and make it kick ass is cool by me. And like musical mashups, video mashups are just as underground and, if you dig deeply, equally awesome. (Any time I’m feeling down, I go to YouTube and call up Tunenvy’s “Barney Crank That Soulja Boy,” a video of Soulja Boy’s eponymous crunk hit as “performed” by Barney the big purple dinosaur. “Youuuuu!!!”) DJ Roonie G does a little of both, mashing and synchronizing songs and videos together. His attack is pretty ingenious, mainly because it allows wallflowers to just sit back and not feel like they’re total losers. On Friday, the resident DJ at the Mirage’s Jet Nightclub in Las Vegas comes to town to perform at his regular Cowtown haunt, swanky nightclub Chrome. Visit www.djroonieg.com.