I received a web link to an “amazing” unusual jigsaw puzzle in an e-mail. It is simple, but different, because it was a moving puzzle.  Just grab the pieces with your cursor and move them into place...
In case you need more puzzles and games, here are a couple of more links:
Jigsaw Puzzle with adjustable resolution
Addicting Puzzle & Board Games
ParachutePuzzle

Something truly “amazing” is the Clock that is composed of just regular keyboard characters and keeps time with a sweep second hand. Try moving your cursor fast around the screen and watch the clock chase the cursor...
Clock03

At Xmas time I often receive an animated Xmas or Happy New Year card or two. Here is a link to some of the best by Jacquie Lawson....

NOTE: You will need to install “Macromedia Flash Player” to play these games.  If you don’t already have the Flash player, you can download/install it here:
Macromedia Flash Player

Here is a set of pictures I classify as “Optical Illusions”...

Bridge_Ships

Columns

Concert_Town

Deer_in_Woods

Faces

Flowing_robes

Horses_Rocks

Its_a_Puzzle

Liar

Mobius_Band

Moving_Rings

People_Faces

People_People

Same_Size_Guys