Who's In It: Ryan Reynolds
The Basics: Ryan Reynolds is a contract defense employee in Iraq and he's been kidnapped, shoved in a box underground with a cell phone and a lighter, and left to figure out what to do next. He makes calls to 911, his employers, his family and no one can (or is even willing to) help him. His kidnappers call him too. And he's got limited time and air. It's kind of like if Saw were a one-man show in a tiny theater.
Whats The Deal: What I like most about this is that it's really a horror movie about cell phones. And not the ha-ha-bad One Missed Call kind. He loses bars, calls get dropped, he gets sent to automatic voicemail or to underlings with no concern for or even belief in his situation. He encounters almost every problem you can have with modern communication so his shared experience of this universal frustration is what will keep you pulled along with the plot much more effectively than trying to imagine yourself buried alive. It'll confirm your unspoken feelings that they're the worst invention in the world and our lives were easier and calmer before they started sending their microwaves into our ears.
Effectiveness As Political Commentary: There's an element of "look what happens when you run off to profit from war" that's too easy and obvious--and for all we know it might give actual wartime kidnappers ideas they wouldn't normally have--but at least it doesn't try to divorce itself from its geographic and political context. And you can ignore all that subtext if you want.
Effectiveness As Gimmicky Thriller: In spite of the way the movie allows Reynolds--for the sake of cooler camera angles--a larger than normal coffin to flail around in, it won't do one thing to diminish the awful claustrophobic empathy you'll experience because the movie refuses to let you out of the box and see the people he's talking to. It's the kind of hold-your-breath thriller you'll watch and never want to sit through again, mostly because it's unpleasant, but also because you know you wouldn't be half as resourceful if it happened to you.
One Nagging Question: If the grave was shallow enough to hear stuff taking place above ground on the surface then why not try to break it open and dig your way to more air? Uma Thurman just punched her way out.