I think it's pretty original. There's not too many movies where there's deliberately no real substantive plot other than a bunch of amusing shit that happens. This movie had the storyline depth of Lord of the Rings- (extremely non-existent) but they weren't trying to hide that. This movie is the antithesis of the majority of the movies that come out each year which end up sucking. Movies that are intended to be serious with elaborate original plots. I.e. (off the top of my head, recent movies Ive seen) Manchurian Candidate, King Aurthur, Born Identity...and the sequel.
It was just a movie about social outcasts. Napolean's character was funny, so were the rest of the characters. Take it for what it is.