Do you recall a television game show from many years ago, called Concentration? It's where you click boxes, or in this case cards, remembering where the various cards are until you have eliminated all of them off of the game board.

This is the digital version of the old Concentration game and it's actually quite fun and challenging to play. It has a built-in timer so the player can try to best his/her own score.

This comes complete with the full and portable (see FAQ page for explanation) versions!