Fermat's room

I rented this Spanish language film on Lovefilm. It is about four mathematicians who are summoned to a remote venue for a weekend retreat of problem solving. When they get there they discover they have been trapped in a room and are sent maths puzzles via a PDA. If they fail to solve them, the room starts to shrink. I found it quite an interesting thriller, as the four try and work out who might want to kill them. However, maybe I found it interesting partly because I like both maths and Spanish.