Comedy stars from ‘SNL’ and elsewhere make beeline to iO Theatre

Things have been hopping at Charna Halpern’s iconic iO Theatre, one of Chicago’s premier incubators and presenters of improvisation. Earlier this week Hannibal Buress surprised the iO crowd by showing up to do an hour of stand-up on the theater’s open-mic night.

Coming up: Some of the former and current “SNL” cast members in town for the opening of “Saturday Night Live: The Experience” at the Museum of Broadcast Communications on Friday have decided to do a pop-up show at iO at 10:30 p.m. Saturday. Performers scheduled include Tim Meadows, Luke Null and Chris Redd — plus “The Daily Show” writer Josh Johnson, standup comic Kristen Toomey and members of the Threepeat group.