I just played my first games of Blokus last night. A very interesting game where you have pieces shaped like all the Pentominos and 4,3,2 and 1 inos, and you have to try to put down all your pieces. Your pieces can only touch by their corners.
Lots of interesting strategy in this game.
It's very interesting with multiple players, because you can quite effectively gang up on other players to make sure they don't win, which limits the search space for the remaining players.
Excellent learning and strategy game that has lots of deep math in it.