My first thought is a candle. Jenni has a great tutorial on this page...
Stamped Candles
Second, go to the
"Anything But a Card" gallery and browse around. There are altered clipboards, journals, photo albums, lunch tins....
the subtitle for the gallery says
"anything that you held still long enough to stamp!" Cracks me up every time I read that line. I had a very docile cat. He would sit on my lap for hours, but I never tried stamping him.