This one sort of came out of nowhere. It's described on the poster as Doctor Who meets Shaun of the Dead, and that's a pretty apt review. It stars three friends, two of which are uber-nerds, with the last being a cynical "normal" person. The lead is played by Chris O'Dowd (Roy from the IT Crowd) whose particular quirk is time travel.
The story starts off with "Ray" getting fired from his job as a "time soldier" at an amusement park. Once our heroes have hit the bar to drown their sorrows is when things get fun. As Ray goes to get the next round of drinks, he encounters a woman who claims to be a time traveling operative, in charge of repairing leaks in the timeline, and she's just so honored to meet such a crucial figure in history. Of course Ray assumes that she's just putting him on at the behest of his friends as a prank. Until he goes back to his table, and then they find the time leak.
Basically, it's a fun little romp through time that doesn't take itself too seriously, and yet somehow manages to adhere to most of the basic theories of time travel and paradox, up until a certain crucial moment in the plot. I highly recommend checking it out if you're in the UK, or whenever they decide to release it here in the states.