TUESDAY, MAY 20There’s nothing that gets our fists pumping like Green Day’s lyrics laid over Missy Elliot’s beats. Finally, there’s a party to celebrate the mashup craze. Become a “Bootie Initiate” every month at the Bootie Boston bootleg mashup party at the Middlesex Lounge (315 Mass Ave, Cambridge, 617.868.6739). You’ve probably seen the event’s intriguing flyers, which depict the mugs of two famous musical artists melded together to form one odd-looking head. (Our favorite is the half-Britney,half-David Bowie.) The night offers DJ-spun mashups and live musical acts. Tonight, catch a multimedia performance from Zebbler, a/k/a the guy who shut down Boston with the Aqua Teen Hunger Force LiteBrite scandal. The event is free and runs from 9 p.m. to 1 a.m.-- Sarah Shanfield