Shrinky Dinks

These are fun and the best thing is the Dollarama sometimes has them or the special plastic to make them

"The very first SHRINKY DINKS were sold on October 17, 1973 at Brookfield Square Shopping Mall in Brookfield Wisconsin. Since that time there has been over 250 different Toy Activity and Craft Kits created and marketed. 

SHRINKY DINKS SHRINK to approximately 1/3rd their original size and actually become 9 times thicker. Simply place the SHRINKY DINKS piece you created into a Home Oven or Toaster Oven for 2 magic minutes. Watch as your creation gets smaller and smaller. 
It's "MAGICAL" and it's so quick and easy to do! "

http://www.shrinkydinks.com/