Besides the 24 episodes as seen on TV, the set also includes a few features like: looking at the theme song by the Barenaked Ladies, a gag reel, and three segments where the actors ask each other questions. I picked up my copy at the local Target which had an exclusive fourth disk that included the show's San Diego Comic-Con panel discussion from the summer of 2010 (bridging season 3 and 4).
As most know, this happens to be one of my favorite comedies on TV right now. I love the whole geek-vibe of the show (from the science terms to the social awkwardness to the comic book references).
