It doesn't embed, so to play the game you need to click on THIS LINK.
The game will flash a sequence of numbers on the screen - very briefly. Then the numbers are replaced with circles. You then click the circles in the same sequence as the numbers. It appears to be a test of short-term memory. I supposedly have a "brain age" of 23.
Update: Redone Oct 2009 - brain age 20.
Update: Redone Aug 2010 - brain age 20.