I've aways wanted to make my own rubber stamps. This is fairly easy and can even be attempted with your kids.
You can use a number of items to make impressions onto your clay; cut-glass vases, graters, rough wood siding, watch springs and a roll of wire are just a few I tried. You can also add tiny clay balls or snakes to a flattened ball for a different look.
Place your finished stamps on a cookie rack to dry overnight.