For extra craziness, only have two players, and let both of them control the gray pieces.
Mundis Taasen, ruled by the geometry of the sphere
(will okay, circle, but still)!

...wait a minute... the lines are
all trajectory lines? Because, that would have your pieces moving all diagonally and curvy-like right from the start. I figured more standard chess-rules applied (pawns move 1 square forward, or two on their first; Knights move in L-shapes; etc.) except in the center.
I'm curious about this, either way... I think I would actually like to try playing with a set like that someday. It looks pretty cool.
Hello! ^^
AKA: Mittens (also Milly) ~My deviantart page~ Regularly updating lately! Yay!
"You know, I’m really glad I don’t use my butt for anything except sex." ~
Amaranth the field nymph, Tales of MU^ I wish this is how butts worked. Alas.