I got a note the other day from Ryan, who told me about a site called "Creativity Games," which is very cool.
I'm a big believer in doing puzzles, word games, logic puzzles, etc. to challenge your thinking, and there are some good things going on at Creativity Games. Check it out - I think you'll like it.
Also, if you like puzzles, I highly recommend subscribing to Games Magazine. I started reading Games Magazine when it first came out over 30 years ago and still love it. It has just about any kind of puzzle you can imagine (crosswords, cryptograms, word search, mazes, logic puzzles, sudoku, "what's different about these two pictures," and much more).
I believe doing these sorts of puzzles helps keep you sharp, opens your mind to better observation and analysis, and generally make things fun.
Got any other great creativity resources? Please share!