Puzzles

Alright, you like Sudoku, so now you should try Hidato

This site is unbelievable: http://www.stetson.edu/%7Eefriedma/puzzle.html

If you like puzzles, you must check out these online versions of the "Rush Hour" puzzle (they're very addicting): http://www.puzzles.com/products/rushhour.htm#Play%20Game

Here's an interesting puzzle site by a mathematician who consults for the TV show NUMB3RS: math puzzles.

Also, you probably should check out this 4D Rubik's Cube. It's fun to look at.