Normally I don't care what's happening on WiiWare, so when I read about Contra Rebirth this afternoon I was like "whaaaat!!" and downloaded it immediately.
After a few plays, I can confirm that it's pretty amazing. Inventive bosses, levels that completely change mid-way through, rock-hard difficulty, great music. At one point, you have to jump along a herd of robot flamingos while being chased by a truck. And you escape by jumping onto a missile! I love this game.
It can be played with the classic controller, of course, but what's interesting is that is can also be played with the Wiimote, and you shake it downward to switch weapons. If I'd read about this feature I'd have laughed at it, but it's actually incredibly responsive and feels great. I still prefer to play with the classic controller, but it's good to know that the Wiimote is decent enough. All buttons are configurable.
I also got Nyxquest, which is an incredibly simple concept but great fun. Situations where you have to jump across platforms while dragging objects around with the Wiimote feels like a perfect multi-tasking action puzzle.