Charlie Sheen will appear in the second episode of GSN’s new primetime daily strip series Drew Carey’s Improv-A-Ganza, which will air April 12. Sheen’s gig is billed as “an impromptu appearance.” The place and timing of the its taping are noteworthy: It was done at the MGM Grand Hotel and Casino in Las Vegas on Jan. 18. That is a week after Sheen’s weekend-long binge in Las Vegas in the company of porn stars and alcohol and a week before the 36-hour bender at Sheen’s house with porn stars and drugs that ended with him in the hospital and led to the production shutdown on Two and a Half Men and ultimately to Sheen’s firing from the show. The cast of Improv-A-Ganza, which seems to be in the vein of ABC’s Carey-hosted Whose Line Is It Anyway, features severals alums from that show. It includes Carey, Ryan Stiles, Colin Mochrie and Greg Proops. Sheen is now embarking on a month-long tour.