Memory game (Concentration) for you to try for yourself.
If you haven't played this game before the rules are very simple. There are 36 squares that conceal 18 pairs. You just select two squares. If the two you select match then they will remain visible, if they don't then they will disappear again after a second or so. The counter button at the bottom tracks how long it takes you to match all of the pairs. If you want to start over just press the counter button and the whole thing will be randomized for you to start over.