Step one:
Follow the moving dot itself... it stays pink.

Step two:
Look at the cross in the middle... what color is the dot now?

Step three:
Concentrate hard on the cross... the pink dots will disappear.

This is amazing.. I had seen it before.
Check out this site
Optical Illusions and Visual Phenomena (http://www.michaelbach.de/ot/)

Thanks for that site:)

There were a few on there I had seen before, but a lot more to check out :)