Altruistic Comedy
When do something funny or leave something humorous where you are not present to witness the laughing of the audience.
Writing on a small piece of paper one of the following:

"Don't slouch"
"You've changed"
"Don't forget"

..and putting in a stranger's pocket when they are not looking.. they leave and you never see them find the note. This is Altruistic comedy... comedy for the benefit of others rather than the gratification of seeing the laughter.