"21 Jump Street" reaps the benefits of having a stocked comedic cast, which helps it succeed despite the overall inclination towards being a slightly altered version of the typical high-school film. The gangbusters pairing of Channing Tatum and Jonah Hill is the most prominently ingenious decision, but having a mix of famous and more indie types (taken from Youtube, "Scott Pilgrim," and NBC alike), all exceptionally compelling performers, draws the audience in even further. Add to that an above-average sense of humor that slants into the meta- and into surrealism at times, and you have a comedy that will appeal to all sorts of viewers.
I know only enough about the television source material to have gotten the big climactic in-joke. I don't think that really mattered. What's here is a twist on the classic tropes of the jock and the nerd, which comments on how times can change very quickly and how social strata evolve accordingly. Tatum and Hill start playing exactly the roles you would think (the former popular but unsuccessful, the latter shunned but perennially on the honor role), but slowly and believably (after bizarrely becoming best buds at a police academy and getting an undercover assignment at a high school) move into acting against type.
I'm not really into revealing too much about movies I find funny, since I think even more than being blindsided by a twist in a thriller I like being surprised by laugh-out-loud moments. What I can say is that the first half is much more successful than the last one (largely due to the presence of an excessively profane Ice Cube as well as some off-the-wall drug humor). But "21 Jump Street" manages to stay at least moderately cohesive wall-to-wall and expertly retains interest all the way through the wacky credits. Apparently directors Phil Lord and Chris Miller (previously known for "Cloudy With a Chance of Meatballs") are following up this work with a picture about Legos. I wouldn't have given it a second thought before, but maybe I'll give it a whirl now having seen what they're capable of. B