Over the past few years, Texas Hold Em has become a television phenomenon. You wouldn't think watching other people playing cards from your sofa would be exciting, but witnessing the World Series of Poker on ESPN manages to convey the giddy, dangerous rush of high-stakes gambling.

There's a reason why blackjack hasn't been as successful as a spectator sport. First off, there's no bluffing. And your only competition is the dealer, who let's be honest, is going to win most of the time. Otherwise casinos wouldn't offer the game.

This problem is exactly why a poker movie like "Rounders" was so thrilling and a movie like the new-to-DVD "21" is so hopeless. Stripped of the action of the game itself, Kevin Spacey and the rest of the unfamiliar young faces in "21"'s cast flail and overact like crazy trying to make the game jump off the screen. It doesn't work.

"21" is an adaptation of the bestselling book, "Bringing Down the House" – a chronicle of how a bunch of MIT math nerds devised a system of counting cards, using probability and other brainiac theories, to fleece Vegas. But while the book carried a cool illicit rush, the movie just feels as watered-down as a complimentary casino cocktail.

Spacey plays the MIT professor who recruits his "Rain Man"-esque students into the scam. He's like Fagin in "Oliver Twist," a pied piper luring these young geniuses into crime by flattering their intelligence. The star of the film is an unpopular nerd named Ben, played by newcomer Jim Sturgess, who can't say no to Spacey because he finds the money, the popularity, and the girls (Kate Bosworth in particular) too irresistible. There's also a bunch of convenient hooey about how he needs $300,000 for Harvard Medical School.

A movie like this is only as good as its card scenes, something that "Rounders" turned into gut-wrenching suspense worthy of Hitchcock. In "21," these scenes a total bust. "21" is predictable, formulaic, and for a movie about math stars, not very smart. Maybe Spacey and company should have tried their hands at roulette or pai gow instead.

Now for a look at what else is new on DVD: in "Harold and Kumar Escape From Guantanamo Bay," a pair of smart-aleck stoners return for a sequel; in "Shine a Light," Martin Scorsese captures the Rolling Stones in concert; and in "Inglorious Bastards," a 1978 Euro-cult film about WWII POWs gets a deluxe edition.