Several years ago there was a product sold by Clearsnap called Penscore.  Since then the name has been changed to Magic Stamp. 
Magic Stamps are approx. 3" x 4" and can be heated and molded to create your very own one of a kind stamp.

Here's how:
1.  To begin, select something to mold and place it in front of you.  This could be a pile of rubber bands, a rubber stamp, artwalk clay molds, the bottom of your shoe or anything else that has a nice deep texture or design. 
2.  Set the Magic Stamp down and with a Crafter's Heat Tool** heat the surface for approx. 1 minute - 1-1/2 minutes.  It is important to keep the tool raised at least 1" from the Magic Stamp and that you keep the tool moving to heat the surface evenly.  Heating in one place for too long and too close may cause the block to scorch.
3.  Stop heating and quickly lift and press the heated side of the block down onto what you are molding.  Press firmly and lift after 15 seconds.
4.  Check your design.  If it looks like a nice impression you are ready to stamp.  If it doesn't look like much happened you can reheat and remold the Magic Stamp.
5.  When you are satisfied with your design you can ink it with any type of ink (I prefer Vivid Dye Ink*) and stamp the image.  Experimenting with different amounts of pressure when you are stamping will change the image greatly.  It is also fun to ink the Magic Stamp with several colors at one time.
*If you would like to stamp on Fabric be sure to use a permanent ink.  Colorbox Crafter's and Lumiere Paints are favorites for this.
6.  After stamping you can wash the Magic Stamp with water.  The design will remain molded until it is reheated and remolded.

**A Crafter's heat tool is what rubber stampers use when the emboss and image.  The tool sometimes looks like a hair dryer, but gets much hotter.

Magic stamps are perfect for fabric stamping, great for creating background papers and so fun and easy for kids to use!!!!