I noticed that Improv-A-Ganza had disappeared from GSN's evening schedule. This could have meant that the season ended and we would have to wait to see the next season. But, Drew Carey posted on Twitter back in August that GSN didn't order any more episodes.
Drew still owns the rights to the show, so it could return at some point in the future, but for now, the show has ended. If you didn't record the shows, better head on over to the GSN site to catch them before they're gone. There's also some good videos in the Blog section on the behind-the-scenes events.