It has become traditional, in our little family, for me to make themed t-shirts for birthday party favors. I started it when my son was three, although I didn't realize that I was starting a tradition until the following year, when he said let's talk about the birthday shirts! I started out with iron-on transfers (vintage digger, old-school skateboarding), then did one of my glitter tees (t-rex), & this year it's a straight-up screenprint:
I'm so used to printing tiny line drawings + text that it was a lot of fun to do something bigger & inkier & less fussy.
I felt a little unsure about doing the shirts this year (what started out as a sweet way to avoid sugar-filled goodie bags for a few kids has turned into a lot of shirts!), but now that they're done, I love them. My kid loves them, & my husband loves them enough that he's handed me one of his own tees for printing, please. Now that those are taken care of, I just have to figure out how to get the Transformer head thingy onto a cake (I found this site, though, which lists more cake image transfer options than I ever dreamed, so I think I'll be able to work something out).