Famous necker cube illusion.

Cool stuff!

A simple optical illusion, using the technique described here.

A Japanese illusionist dresses up as an old man and performs some bizarre tricks, especially at the end.

A very good video, made for Samsung.

Great optical illusions, shown in the TV program Bill Nye the Science Guy.

A Kitten's Reaction To A Classic Optical Illusion

Student Appears Twice In Multi-Exposure College Class Photograph Prank

Man Interacts With Optical Illusion Trick-Room