I used the adhesive magnet strips you can get at craft stores, and just cut it up into little pieces and stuck them on the back. So easy!
And now they're ready to play with on your fridge, a cookie sheet, or with the quiet book matching game I made to go with them.
(Here's a preview of the first page)
If you don't feel like using it as a quiet book, it would also make some great coloring pages! Or you could use it as a quiet book or file folder game just with paper pieces to match if you don't want to take the time to sew all the pieces.