[oscilloscope]

Play the board game Go. It's simple, tactile and astoundingly complex. I've found wrapping my head around that game is a similar experience to wrapping my head around programming concepts.

Your son will come to you to play board games, whereas teaching programming is something where you'd be driving what your son learns.

Building a Go game on the computer is also not that difficult-- but developing AI for it leads deep into math and computer science.

http://en.wikipedia.org/wiki/Computer_Go

[btilly]

The nice thing about go is the handicap system. You can play mutually fun games when there is a very large skill difference. Western games like chess? Not so much.

Plus the simplicity of the rules is helpful for learning for younger players. The rule of thumb is that if they are old enough to not eat the pieces, they are old enough to try playing.

[eru]

Other boardgames, say Euro style board and card games, are also fun and teach basic math, getting along with others, optimizing interaction within a framework of rules, creativity. They are also fun. Your child has to be a bit older for most games, though. Around 5 you can start with the easier games, if they youngsters are bright enough (and have enough patience).

You may be able to start with Go earlier, since the rules are so easy. Just be sure to start with a very small board.