Best Website to Play Free Brain-exercise Games?

This one is great – it's what fighter pilots use in their training. I once managed to get 21 seconds….you'll see what I mean. Have fun!

http://members.iinet.net.au/~pontipak/redsquare.html

Suggestion:

I had a pretty hard time beating this game: http://www.notdoppler.com/splitter2.php