If nothing else, Chicago's improv community has proved that improvisation is a limitless form that can be molded and warped to suit the performers and audience. On the other hand, the weight of improv history and tradition is an awful cross to bear. There's an urge to add flourishes to the palatial mansion of improv built over the last half century--and a concomitant risk that improv will become too academic. That's why ComedySportz, with its emphasis on improv for entertainment's sake, will always be among the hardiest of troupes. Its game-oriented style isn't for everyone: character development and subtlety of tone are often whisked away by the show's rapid pace or buried under an avalanche of one-liners. Still, the ComedySportz formula--a good-natured competition between two three-person teams--is a winning one, and these seasoned performers play off one another's strengths exceptionally well. The troupe's recent move to a larger, 150-seat venue (at Organic-Touchstone's former home) ought to pay immediate dividends: the bigger, noisier, and more appreciative the audience, the stronger the ensemble's efforts. ComedySportz, 2851 N. Halsted, 773-549-8080. Open run: Fridays-Saturdays, 8 and 10:30 PM. $15.