SSBM 1-player not fun?? That is by FAR the most fun you can have playing single player in any fighting game ever made. Period.
For me, there isn't a single game on N64 that I liked. I've tried any number of them and I 1) hated the controller 2) thought the graphics were universally ugly, and 3) never found a single really engaging game.
I'll throw Tales of Symphonia in there for great GC games, too