Back in the mid-80s, someone at ImprovOlympic gave me "An Improvised Almanac," a couple of faded pages that had been photocopied so many times the type was a ghostly gray. But in the right light you could see that this was improv gold, line after line of helpful maxims like don't deny; heighten the reality; don't just comment on the action, do something. I never saw anything like it again until I read the page proofs for The Second City Almanac of Improvisation, edited by Anne Libera and coming out this month. It's packed with reminiscences, pontification, old arguments, new theories, descriptions of games, and wise advice from 24 current employees or alums of Second City (including at least one, the late Del Close, who'd be shocked to find himself there). This almanac reveals that the earlier one was created and distributed by Jonathan Pitts, today the executive producer of the Chicago Improv Festival. Now Pitts--whose almanac is reprinted in the Second City book--has given one of the festival evenings over to many of the performers and teachers whose writings appear there. And if the show is anything like this fascinating crazy quilt of a book, three generations of opinionated improvisers will be finding dozens of ways to agree and disagree at once, playing together as they fight, asserting they're all on the same page while contradicting one another in a thousand little ways. Among the performers are Dan Castellaneta, Michael Gellman, Tim Kazurinsky, Keegan-Michael Key, Susan Messing, Mick Napier, David Pasquesi, and Ron West. Athenaeum Theatre, 2936 N. Southport, 312-902-1500 or 773-935-9810. Saturday, May 8, 8 PM. $25.