Nintendo's patented an inflatable horse-riding seat controller thing, as you can see on Siliconera. Try not to laugh.
You blow it up, fit your Wiimote in it and sit on it. Or your kids do, at least.
You're supposed to simulate riding on it, as the Nintendo patent describes, “a raised hand for balance as in Bronco riding, a lasso, a sword or other weapon, etc.”
Sounds amazing. Will never come out. Look at it anyway.