The Man Who Knew Too Little
This was something I'd never heard of before, but it was quite funny. Lots of British comedy faces in it, Americans would probably only recognise Bill Murray and Alfred Molina (Spider-Man 2). It was very 'Inspector Clouseau'-esque. Murray is gormless and gullible as an American tourist in London who thinks he is performing with the 'Theatre of Life' live-action-role-playing company, but is actually mixed up in a real-life espionage culminating in an assasination attempt. The script is so ludicrous that it is feasible Murray could think it was all just a game.