Hmm...
Super Smash Bros Brawl (This one is like the defining game for the Wii, Or so I've been told)
Bully: Scholarship edition (This game was by rockstar. It's a gem of a sandbox game, If a tad easy. Kinda hard to find)
New Super Mario Bros. WII (I guess if you like 2D Mario...Didn't really do anything for me)
That's all I got.