I spent Saturday babysitting my nephews and having a picnic at a local park. We walked down to a creek, ate jello, and looked for lizards. Sean made a joke about butterflies: "What do you get when you see a butterfly on a flower? Give up. Butterfly butt-crack."
It cracked him up. He giggled.
And the laughter brings karma to the world, although I still don't get the joke.