Cyberbike Magnetic Edition
The Cyberbike Magnetic Edition is a bike peripheral for the Wii, made by Big Ben Interactive. At the time of its release, it actually costed more than the Wii itself. The bike plugs into the GameCube controller slot; as such, it can be used with any game that supports the GameCube controller, and it is only compatible with RVL-001 Wii units due to the absence of GameCube controller ports on later units.
It was released in the US and Europe, and bundled with a game called Cyberbike Cycling Sports, the US version of which is notable for being uncommon.
On Amazon, the accessory got mixed reviews. The bike got a sequel called Cyberbike 2 for the PS3, with a game called Cyberbike Cycling Sports 2.