We're usually not huge fans of Jack Black movies, but Be Kind Rewind sounded sort of interesting, so we rented it recently to check it out. We've heard people that hated the movie, and other people that thought it was pretty funny so there was no way to know for certain unless we watched it ourselves.
The movie is not incredible, it has the level of quality that you would expect from a Jack Black/Mos Def/Danny Glover movie, but it's actually pretty funny. Mos Def and Danny Glover run a VHS rental shop in New Jersey and when the all of the tapes are erased, they decide to tape their own version of the movies (Sweded!), which turns out to be highly hilarious and successful.
Quick vote: The movie was actually pretty funny, although quite stupid. We liked it!