Over the weekend, I was reminded how great card games are for teaching, reinforcing and exploring math concepts from the most basic to the most abstract and advanced. Games like Cribbage are very good for this, as are any other than involve manipulating values. Also, many games can be adapted to apply these ideas. Cards can also be used very explicitly, in ways such as the one described in this video. The narrator is a bit intense, but the idea is very solid and could be a lot of fun.
It is also worth checking out the sites on the right sidebar of this page, and if you search "math" in the box on the top of the page you will come up with past links I have posted.