Variants

Go on a 2 by 2 Board
Mathematical analysis of the outcome of go on a board with four or fewer vertices, under a suitable mathematical ruleset.
http://brooklyngoclub.org/jc/go2by2.html

Go Variants
Slightly different games that can be played on a go board or in a similar style as go.
http://www.win.tue.nl/~engels/go/variants.html

Quantum Go
A tool to teach principles of Fault-Tolerant Design, based on the game of go.
http://www.tipjar.com/dnconsult/QuantumGo.htm

Round Go Board
Print out this round go board from a PDF file and experiment.
http://www.youdzone.com/go.html

Tanbo
Offers rules and game information.
http://www.gamerz.net/pbmserv/tanbo.html