Don't know if I can narrow down to just one....
Some choice(s) would be:
1) The Matrix (the original one - not Reloaded)
2) What About Bob? (with Bill Murray). Especially funny if you have relatives like that.
3) Throw Momma From The Train (with Billy Crystal and Danny Devito). Hilarious - see #2.
4) Star (BMW Short film with Clive Owen). I still believe he should be the next Bond.
Jonnie