Take a picture of a kid you know well, your niece, nephew, younger sister or brother.
Then, make a postcard out of the picture and mail it to the kid.
My photography teacher was reviewing some of my photographs, and he stopped at one that I had taken of my little sister. “You should print this out a little smaller, put a stamp on the back and then mail it to her,” he said. “Kids like getting stuff in the mail, and they’re just blown away when they see a picture of themselves arrive like that… They feel famous, in a kid sort of way.”