30 Rock keeps living up to its excellent track record with another ridiculously funny episode, replete with absurd scenarios and even more insane characters.
A while back (actually, the fifth episode of Season One), Jack said he was studying comedy by watching a classic NBC sitcom, namely Friends, and asked Liz what happened between Ross and Rachel. Coincidentally, or maybe not, David Schwimmer, aka Ross, appears in this episode as the actor playing the titular Greenzo, an environmentalist superhero who's supposed to teach kids about the dangers our planet faces ever day. Unfortunately, "Greenzo" gets full of himself and starts a "green crusade" of sorts, openly challenging Jack. Meanwhile, Pete, who's still staying in Liz's apartment, makes people believe he's cheating on his wife, and Kenneth invites everyone to his birthday party, which inevitably ends in a way no one wants to remember.
After Jerry Seinfeld, Will Arnett, Steve Buscemi and Carrie Fisher, the show confirms its gift for guest stars thanks to Schwimmer, whose manic performance (a clear parody of Ross Geller) was more worthy of an Emmy nomination than Buscemi's (still very funny) private eye spoof. The Pete subplot is even more brilliant than the vasectomy gag in the previous season, and the whole mess involving Kenneth's party should be used to teach budding screenwriters how to do comedy.
Oh, one more thing: given the environment theme, an appearance by Al Gore was inevitable. Less easy to predict was the fact that he almost steals the episode with just two lines. Maybe he should give acting a serious thought: how many non-professionals manage to outshine Tina Fey in only ten seconds?