Christopher Nolan's first film is a 'no budget' black and white film about a unemployed writer who begins following strangers, which in turn leads to robbery and also violence. It is very good.
Like in his later film 'Memento' he doesn't present the story in a linear way. Instead it jumps around somewhat so you end up really sucked in trying to piece it all together and early, apparently random, shots take on significance as the film progresses. This style also means the twists are much more effective.
Definitely worth seeing if you get the chance (especially if you like his later work and/or Film Noir)