The movie is part rap Spinal Tap, part Loaded Weapon I, part Mad magazine. And, like those forms of parodic tribute, it assumes a very specific knowledge of the performers, the music and videos being parodied, a certain level of hipness. In other words, if you don't know rap, forget about it. You'd do just as well taking an SAT prepared by extraterrestrials. If you know the turf, though, you're in for some fun.

More clever in idea than execution, this mockumentary about a trio of middle-class poseurs masquerading as the World's Most Dangerous Group Not Named N.W.A (Rock even sports Eazy-E's trademark jheri curl) is at its best when it's spoofing the songs of the time — Sweat of My Balls, a hilarious reworking of Kool G. Rap & DJ Polo's Talk Like Sex is Weird Al–level genius.

Not all Saturday Night Live sketches succeed in the transition from small screen 5 minute slot to hour and a half, with CB4 a fine example of one with mixed results. Rock and his group do well in mocking not only the blacks, but whites and all number of classes along the way, except the story doesn't quite manage to hold it's own as the joke begins to tire after the first hour.

The movie has bounce and bite, but it skitters around too much. Its needle is hip-hopping around between too many grooves.

Made in the shadow of Wayne's World, CB4 is another Saturday Night Live-related music parody, this time skewering rap instead of heavy metal. Desperately uneven, it works best as a string of sketches about the title band, three guys who were born Albert (Chris Rock), Otis (Deezer D) and Euripides (Allen Payne) until they realized it might be more profitable to rename themselves MC Gusto, Stab Master Arson and Dead Mike.