Here's something cute for you. My friend's son's first letter to Santa.
I helped a bit with the words, but he decided that it needed hand prints. He sticks his hand down on the paper and then tells me to draw around it. It's really cute. I think he knows it's a way of saying, 'I did this, this is me'.
We even taught him to lick the envelope. For some reason he loved it! Kept licking it until it was a soggy mess. Oh well, Santa won't mind.