I saw a really cool memory game online recently. Modern and hip...but $40. So I decided to make my own. Found the 2" chipboard squares at the local Robert's and used all my scrap paper. I bought 40 squares and it was $4.50 (had a coupon).
I left the other side blank so the chipboard is showing, but you could choose one paper (solid or patterned) to mount to the back side for a more finished look.
I used Duro all-purpose spray adhesive (found at JoAnn Fabrics), but there are many brands and you can find it at any craft store. It is an aerosol can. I just followed the instructions on the back of the can: Spraying both the back side of my paper and the chipboard for a more permanant mount.
***check out the comments for some cool variations. a personal fave: using photos of family members for your memory game. Most of our relatives do not live close and what a great way for kids to feel connected. I love it!!