Last summer I wrote about using the card game "Old Maid" as a way to practice math skills. Rather than looking for two of the same card, you are looking for a matching question and answer. You can read the original post here for more information if you'd like. At that time I included a download for a version of the game for writing a system of equations from a word problem.
Here are some new versions that you can use as well. Feel free to create your own and share as well :)
Grade 1: Adding Two Digits Numbers
Grade 8: Solving Equations Using Square and Cube Roots
Geometry: Congruence Properties