Brain Exercise
I first learned about the card game "Set" from my mother-in-law this past Christmas. It turns out that my older kids had already been playing it at school for awhile. Now we all like to play it, and my wife spends about five minutes a day on the online version here.
Read the rules carefully, as you might find them confusing at first. The easiest rule to remember is the "magic" rule: if two are and one is not, then it is not a set.
Have fun!