I saw this movie during Flashback Weekend 2002 in Chicago. I had never heard of it, but I stayed for it anyway. At first, I regretted it because it seemed like the movie would be horrible. But as it went on, it turned out to be not that bad.
This movie starts out with this professor telling his students about a project they'll be involved in. The project is each of the students will get one part of a skeleton (not a real one, one used for something like a science class). The students will do something to that part of the skeleton to make it their own. (Like decorate it with things that mean something to them, etc). They will all get together the next Saturday night at a bar and put the pieces back together, hence the title "Jigsaw"
I won't tell anymore except for the killer is so ridiculous, you just have to laugh at its stupidity. If you wanna rent a cheesy movie, this one's great if you don't take it too seriously. Don't expect to scared by this, because if you did, that'd be even funnier than the movie.