"Natural disasters, diplomatic ineptitude, medical malpractice, and gas prices that are rising faster than Hannah Montana's DVD sales dominate the daily headlines. Sure, Jon Stewart helps dull the pain, but sometimes you need to be in the company of live human beings who help you grapple with the issues. And let's face it, giggling always makes grappling easier. Enter . . . MOSAIC, a performance described as covering the territory between performance art and sketch comedy. There are songs, skits, puppets, and guessing games. The four-person show moves at the clip of a ticker on the bottom of your favorite cable news channel and may even address some of the same topics. It's performed every Saturday at 7 p.m. at ImprovBoston."