Here's a book you can pick up, thumb through the pages and find something that makes you laugh. I'd actually considering giving this one as a gift.
Here's some of my favorite entries:
Laughing so Hard you start crying....Awesome!
When your windshield wipers match the beat of the song you're listening to
Seeing old people holding hands
Correctly guessing the actor voicing the animated movie character
The sound of snow crunching under your boots
pulling a weed and getting all the roots with it...awesome!
and I know this one is totally gross, but it's one of my favorites....
When a big chunk of earwax randomly falls out of your ear.
(the whole page on this was funny!)