Klonoa, hands down. One of my favorite games of all time, let alone on Wii. Seriously, if you don't own that game, you need to do yourself a favor and buy it RIGHT NOW. You'll thank me.
I'd say Okami, too, but I'm pretty sure that's too mainstream.
Hamr wrote:The Kororinpa games. Simple concept, rock-solid controls, adorable presentation, and some of the most ruthless level design on the system when played for true completion.
If they had stage descriptions and those descriptions were honest, this is how they would read: "You think you know how to roll a ball? F*** you."
"Oh, you a Super Monkey Ball veteran? Lol that's cute. Maybe you'll be good enough to get a bronze medal!"
Totally need to buy the Kororinpa games now.