Also IMHO Go is a wonderful game for little ones, because they can begin to play so quickly and early on in the game-learning process.
minniemarx, I have played Shogi but not Xiangqi in younger days. Check out the chess variants here:
http://en.wikipedia.org/wiki/Chess_variantsI also enjoyed playing several of the listed variants, including Capablanca Chess, in younger days (okay, let's be honest, decades
). Your son might enjoy the ChessV program, free chess-variant-playing software:
http://en.wikipedia.org/wiki/ChessVAnd, of course, there is the most challenging variant of all:
http://media.fukung.net/images/7571/71_pics_145759.jpg
