[quote name='botticus']Mario Baseball and Golf are good... Timesplitters 2... ditto to the above.[/QUOTE]
Second'd.
I personally love Mario Golf and feel it is one of the best golf games ever.
My roommates are currently obsessed with Mario Baseball. It has its problems (mostly the way the computer handles fielding and the way hits are usually pop flys and almost never grounders), but it is a good game.
Mario Tennis is pretty quality. Turning off the super powers makes it a lot more balanced and fun though, I highly recommend doing so. Keeping them on makes it a lot more of a kids game/a game of luck.
Also, Shy Guy's voice acting and grunts are hilarious in it.