If you want a challenging strategy game for up to 4 players, then Blokus is a great choice. 

It's an exciting game which has simple rules but offers an infinite number of combinations. Up to four players use different coloured and shaped pieces to try and fill as many places on the board as they can.

The rules of play are quite simple, but play can unfold in an almost infinite variety of ways.  The idea is to fill as many squares on the board as you can with your own coloured pieces.  The only rule is that your piece much touch another of your pieces at the corners - and only the corners. 

It's recommended for ages 8 and up.  Blokus was awarded Game of the Year in 2004 and Bronze as Toy of the Year in 2005.