When I looked a little closer, I realized it was written on a paper bag! I bet there are a bunch of people out there who are going to be emailing this to their parents and screaming at them for throwing out their boxes in the attic or basement.
If you're a fan, check it out soon. It looks like the auction ends on Wednesday night. I totally want to see what this winds up going for.
Until then, I've got a call to make....
***A long overdue follow-up to this post: The paper bag eventually sold for $330! According to the seller, "The best part of it is that I only took it to have something to write directions to a party on."