Try this out wow.exe (22kb .exe download): read these instructions carefully first:

1. Download the program above
2. Run the program
3. Stare at the centre of the image for 20 seconds...
4. Really concentrate...
5. Your hand should be on your desk (or on your mouse). Do not move your hand...
6. After the 20 seconds of concentration, look down at the back of your hand (without blinking) ...
7. Don't scream...