Excellent topic!
For me, it'd have to be Bruce Almighty... my girlfriend and I rented it last night... on VHS! :P
Basically Jim Carrey's character gets God's powers for a week while God himself (played excellently by Morgan Freeman) goes on "vacation". Much hilarity ensues.
I'd have to give it a 4 outta 5. The ending got a bit dark for my tastes. Overall though, I laughed out loud a lot.