Blokus

Blokus (officially pronounced "Block us") is an abstract strategy game with transparent, Tetris-shaped, coloured 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.

There is a solitaire variation where one player tries to get rid of all the pieces in a single sitting.

Goal of the Game:
Each player has to fit as many of his/her 21 pieces on the board as possible.