Brilliant satire, but kids need to be old enough to absorb it
This movie definitely has more overt violence and sexual humor than Monty Python's Flying Circus (TV show) or even "Holy Grail." Still, that's not what's most tricky about letting kids see it. This movie satirizes religion with a razor-sharp edge. Fascinatingly, about the only thing in the movie it treats with genuine reverence in the image of Jesus himself, delivering the Sermon on the Mount in a fashion as dignified and realistic as any Biblical epic. But, almost instantly, it shows people mis-hearing and mis-interpreting his words to hilarious effect. Believers of every stripe (religious and political) are depicted as little more than buffoons (a group of rabbis once called this "the most offensive movie ever made"), and the folly of clinging to a faith that, under scrutiny, makes no sense is laid bare time and again. The message -- and there is a message -- of this movie is that you should understand what you believe in. That's a powerful intellectual revelation, but one that pre-teens may not be ready for.
Unlike Holy Grail, this movie is Rated R. The f-word is used about 8 times and there are two full frontal nude scenes both male and female. There's also some comic violence but nothing too bad. If you do not have a problem with your kids viewing nudity, then this movie should be fine.