Dante's Inferno - This trailer is actually for a video game very loosely based on Dante's Inferno from the Divine Comedy. It actually looks pretty cool and there is a movie based on this game already in the works.
http://www.youtube.com/watch?v=KBzq52L3w_g
Cloudy with a Chance of Meatballs - Again loosely based on a children's book, though this version seems to only encourage more gluttony in America, in 3D of course!
http://www.youtube.com/watch?v=1zdPxTXviwI
Year One - full trailer for buddy comedy set in the Ancient World
http://www.youtube.com/watch?v=UQNbYtcv6ZE
Tyson - Retrospective documentary about Mike Tyson's life/career
http://www.youtube.com/watch?v=2ZmrBGwIT8I