For a game with that premise, 
Flow is suprisingly meditative and relaxing. I think it might be the fluid, graceful movement of my beastie.
My hand cramped up, though - I'm not much of a gamer. Give it a shot and be in the zone for a few minutes. You probably need Flash 8.
(found on 
Fark)
P.S. 
Ooohhhh.