It's a simple question. What is the game you are currently playing on the GCN and are trying to beat(100% or otherwise)?
Currently I am playing Super Mario Sunshine but since my roommate does not like the game, When he gets up I'm not sure but I could most likely switch to Super Mario Galaxy 1 or 2. Great games as well as Sunshine, Although they are for the Wii.
Oh, and of course, feel free to recommend GameCube Games to play