MC Chris, with MC Lars, Math The Band. El Corazon, 109 Eastlake Ave. E., 381-3094. 8 p.m. $15. All ages. High-pitched and hidden behind his ever-present low-slung black baseball cap, MC Chris is the comic-loving, videogame-playing antithesis to the common conception of rap music. From his beginnings in Cartoon Network’s late-night programming, most notably as MC P Pants in stoner favorite Aqua Teen Hunger Force, Chris’s natural comedic leanings and lightning-fast flow paved the way for the cult “nerdcore” following, with the Star Wars-centric “Fett’s Vette”–a taste of what collaboration between Mickey Avalon and George Lucas might sound like– and the “nerd girl” anthem titled, well, “Nrrrd Grrrl.” Despite the lightweight subject matter, MC Chris is a legitimately sharp rapper–albeit one who is perfectly content goofing around over a Casio synth beat. NICK FELDMANSage Francis, with Free Moral Agents, B. Dolan. Showbox at the Market, 1426 First Ave., 628-3151. 8 p.m. $22. Not content to simply be a longtime ambassador between hip-hop and indie rock, Sage Francis spends his new fourth album Li(f)e collaborating with a rogue gallery of indie heroes. There are co-writing credits from Chris Walla, Jason Lytle, the late Mark Linkous, and members of Calexico and DeVotchKa. The result is relaxed and naturalistic. Managing his usual balance between self-reflection and self-deprecation, Francis rails against the stifling, contradictory rule set of society and organized religion. If the album is fairly uneven – for every song as quietly great as “16 Years” or “The Best Of Times,” there’s an iffy wobble like “I Was Zero” – Francis’s brave knack for exposing himself goes a long way. DOUG WALLEN