Nacho Libre:
Holy crap was this funny ! I feel this was some of Jack Black's best work. It was laugh-out-loud funny for the first half of the film, then it sort of died out around the mid-point, and picked back up toward the end. Normally I would have been annoyed by the waning of the comedy, but it really was necessary so they could fit some plot into the movie
Don't go to see this movie if you plan to scrutinize it. It is dumb fun for those who just want to laugh. If you don't like Jack Black's work as Tenacious D, but really loved School of Rock, I would have to say you might not like this movie as much as you hoped. It is more fans of Jack Black as the crazy Tenacious D singer who can bring the most random thing into a situation to make it downright wacky.
I would give it an 8.5-10 only due to the sloping off of the comedy around the halfway point, even though it was justified.