It's the story of a jury that has to decide if a man is guilty of killing his own father (and going to the chair for it) or not. The jury consists of 12 men with different personalities, some of them are calm, clever, others are ill tempered, and some others just don't give a fuck and just wants to go home.
So you want a claustrophobic movie? 90% of this movie happens in a small, hot room, with 12 guys arguing. Forget Buried, rent this one. It will make you sweat for sure.
Not much to say about this one... just rent it!