Some images are more interesting than others, and may lead to serious hallucinations. These images are striking either way you put it, and inspiring, too. Not all of them are freely usable but you can easily download them for your personal use or start from scratch in creating your own optical illusions.
optical illusion
Impossible LEGO Landscapes
Here some crazy optical illusions involving LEGO constructions that seem to defy laws of physics and common taste.