Random sale recommendation, I've been playing through Super Monkey Ball Banana Mania but have been a bit disappointed with it, no multiplayer, wonky physics, not a huge fan of some of the visual changes.
Randomly picked up Paperball Deluxe:
Buy Paperball Deluxe and shop other great Nintendo products online at the official My Nintendo Store.
www.nintendo.com
and am loving it. It's obviously lower budget than Super Monkey Ball Banana Mania, but the visual design and music are awesome, and it has great local multiplayer modes. Also allows me to *save a challenge run and come back later* which is huge. I don't know who the hell has time to sit down and play through the Super Monkey Ball Banana Mania expert challenge mode in one go, it's ridiculous.
Anyway, if you like Super Monkey Ball at all (especially local multiplayer), try out Paperball Deluxe.