I had a blast of Super Monkey Ball 2... it was fun but think it's more for younger kids.
Also played Mario Sunshine... typical Mario game, very good if you like that sort of thing (which I do
). Also played Mario Smash Tennis, it was OK but I'd rather wait for a Wii-specific tennis game.
Lastly, had a go too at a Fifa Street Soccer game which I didn't get on with. I love Pro Evo on the XBox and it's just nowhere near as good. It's played on a much smaller pitch, with only 3 players per team, and I just didn't feel that it was responsive... it felt more like luck whenever I scored, rather than intentional.