www.angelfire.com/on/topfen/reflexes.html
reflexes reflexes reflexes

 
Test your Reflexes
Click on "start" first, and wait until the background colour changes.
As soon as it changes, hit "stop". (If you don't like the colour used
you can change it.) The colour can take between 1 and 20 seconds to
change, so keep your finger on your mouse and concentrate.
Good luck!