Cool Stuff People Send Me, Optical Illusions Edition

You may have seen some of these before, but they are still reeking of blogworthiness.




Try to count the number of black dots in the image below:



This one is the coolest. Read the instructions, then proceed. I get how it works, but am still amazed.

Stare at the four black dots in the center of the image for 30 - 60 seconds.
Then quickly close your eyes and look at something bright (like a lamp or a window
with sunlight coming through it). You should see a white circle with an image inside it: