A few weeks ago, Tom participated in a sticker chain letter thing-- he sent a pack of stickers to one person, the letter to some more... anyway, this week he received two packs of stickers in the mail.
When we got the letters, he recognized his name on the envelopes and we had to sing the song from Blue's Clues, "You've just got a letter," which just thrilled him. The stickers were even more exciting. He shared with Chris, Gordon, and me, and put a bunch on himself as well. 
Now, as I walk through the house, I'm finding little "evidences" everywhere-- walls, doors, the bathroom-- cute little stickers all over. It's kind of cute-- nothing like Spider Man to make you smile when you round the corner!