This is probably my favorite Gamecube title... and the odd part is that I'm really not that crazy about the main portion of the game. It's ok, but as the difficulty ramps up, it seems a little gimmicky and requires too much trial and error. It's the minigames that totally hooked me.
Monkey Target is as addictive as any standalone game I've ever played, and as party game, much more fun than anything in Mario Party 4.
Monkey Bowling was also a nice surprise. The gameplay and interface is a much better design than any standalone bowling game out there.
Monkey Golf also suffers a bit from a bit too much "success via trial and error", but it's still good for some laughs.
Monkey Billiards has some camera issues, but again, a great party game.
Monkey Fight, I can take it or leave it, but Monkey Race is as much fun as most kart racers.
Bottom line... forget Mario Party... this is the best party game on the Gamecube.