A recent subject of interest for me is Go, a very old Chinese board game that has
simple rules but very complex strategy. And it does not apply nearly
as well to 'brute force' computer solutions as games like chess which
IMHO are boring :-). I have converted an old rec.games.go FAQ into
STG format in case you want more info about the game.
For ST there are Warwick Allison's GEM port of
X AmiGo which is a weak computer Go player (all are,
especially the free ones) and a text based mgt ('My Go
Teacher') for viewing Smart-Go game records and for playing
Go against another human. 27K/450K
Jan Steen is a quite
well-known GO player who has at least had an Atari ST :).