In order to get some testing of GTP implementations, and to some extent because it's interesting in itself, I have started a Random Go Challenge. For current standings and information about how to participate, see
http://www.lysator.liu.se/~gunnar/gtp/random_go_challenge.html
The software driving the challenge has only been marginally tested so far and there will probably be some initial problems. But please try to connect your programs and see what breaks and I'll try to fix it.
/Gunnar