Many films involve eclectic groups of characters forced to cooperate in a confined space. I love films with character and, for these films, this is an essential element. While the films on this list succeed to varying degrees, the result is usually interesting.
1) A group of four or more people for variety
2) The characters should interact with more than just one or a few characters (i.e. not The Usual Suspects)
3) A (or a series of) confined space(s) with little or limited privacy
4) The space must be difficult to successfully escape
5) Most of the film should take place in the space
6) None from the imprisoned by killer subgenre (i.e. not Saw)
(Some of these I haven't seen, so feel free to let me know when I'm mistaken.)