Cool Math for Kids
Tons of math games, logic puzzles, word quizzes and more

Brain Conflict
Here's a good brain twister.

The Amazing Hondo
You will not believe this magic trick!

The Ultimate Puzzle Site
Brain teasers

Ronan's Online Karaoke
Do-it-yourself karaoke

Thinking Fountain
Experiments, books, etc. from the Science Museum of Minnesota

Eyetricks.com
Great optical illusion site (my favorite is the rotating dots at the bottom of the page)

Learn to Juggle!
Step by step instructions