Blokus

From BoardGameGeek.com:

Blokus (officially pronounced “Block us”) is an abstract strategy game with transparent, Tetris-shaped, colored pieces that players are trying to play onto the board. The only caveat to placing a piece is that it may not lie adjacent to your other pieces, but instead must be placed touching at least one corner of your pieces already on the board.

The game ends when all players are blocked from laying down any more of their pieces. This also includes any players who may have placed all of their pieces on the board. Scores are tallied, and the player with the highest score is the winner.