The trailer for 21 is online, the film from the novel by Ben Mezrich, Bringing Down the House: How Six Students Took Vegas for Millions (Amazon.co.uk / Amazon.com).

The film tells the story of a group of MIT students who are recruited into a card counting operation and head to Las Vegas to take the casinos for as much as possible, and that they did, for it's based on a very true story.

I've read the book and it isn't really an exciting story, more a retelling of events, so seeing that they've really ramped up the repurcussions from the novel to the big screen is a big plus sign, it means the true story is distorted, but the tension and action is ramped up.

You can see the trailer over at Yahoo Movies [Flash:QT:480p:720p:1080p].

I think it looks rather interesting, especially with Kevin Spacey leading the crew and Laurence Fishburne as one of the Casino hard men.