At Brown Owls on Sunday we carved it up, with handmade eraser stamps.
There are HEAPS of tutorials around the internets - our Brown Owls blog post has a few good starters
Sorry for the not excellent photos - these are from my phone and taken at night)
It was a lot of fun, and the perfect little project for one of our afternoons - everyone had time to get a result. I think my little mushroom and cupcake turned out pretty cute - I have a few ideas for some more, and I can't wait to get some more carving done!