The only thing more fun than making the kid laugh is discovering a new way to make the kid laugh. My latest find is nibbling on his fingers. It has to be with bare teeth -- lips or lips over teeth are not nearly so hilarious, apparently. And part of the fun for him seems to be his ability to control the action: he presents the fingers and gets to yank them away once they've been bitten. Uproarious.
Some other things that make him grin, giggle, or squeal:
1. Pinching his fat little thighs. Fingers and thumbs have to be on opposite sides of the femur, but at almost any location so long as they oppose.
2. Saying "peas" while drawing out the long e.
3. Making a noise like a suction cup being pulled off.
4. Rib and belly tickling, especially with long, anticipatory wiggly finger swoop-in. Referred to in our house as fluffy fingers.
5. Classic for a reason: This Little Piggy.