Am looking for a good laugh to watch by myself.
Harold and Maude
Funny, but also beautiful and unusual.
The Life of Brian. When it was first released it caused outrage among churches for it was seen as blasphemous. Some years later I would correspond with our town's methodist minister using quotes from the film's script. And of course there is the final scene with the Pythons each nailed to a cross and singing:-
Always look on the bright side of life!
MR. FRISBEE: I mean, what you got to lose? You know, you come from nothing.
EVERYONE: whistling
MR. FRISBEE: You're going back to nothing. What have you lost? Nothing!
EVERYONE: Always look on the bright side of life!
Dirty Rotten Scoundrels, Best in Show, Ruthless People
Talladega Nights is up there. Office space is too.
Depends on what you like. Grandma's Boy is hilarious no matter what. But if you like table-top RPGs, check out Dorkness Rising (especially with D20 subtitles)