This is, without doubt, the BEST PC-related illusion, I've come across.
1) Relax and lazily stare at the 4 tiny dots in the picture below for at least 30 seconds.
2) Slowly shift your gaze from the screen to a wall near you.
3) You will see a circle of light formed on the wall.
4) Start blinking and continue till you see a figure within the circle.
5) What do you see? Rather Whom do you see?
I tried this a couple of times, to Reconfirm...Man-o-Man........!