The Fun Center was a contraption made by the Starlight Children's Foundation and Nintendo to bring their consoles to hospitals. It consists of a console, TV, and DVD player that can be transported easily through the hospital grounds. SNES, Nintendo 64, GameCube, Wii and Wii U versions have been made.
Perhaps the most interesting Fun Center is the Nintendo Wii version. It was released on June 25, 2008. actually runs on development Wii hardware. You load games onto it and they are displayed in a GUI, which can be considered watered down compared to USB Loaders, especially WiiFlow. In order to get games loaded on it, you had to call Nintendo's Fun Center hotline and use a Windows download manager to download them.
The Wii U version seemed to have the games pre-installed on the system without any different GUI, and the other versions probably worked like a real system would, where you have to use cartridges or discs.
An interesting note about the Wii Fun Center is that a possible system error message was "Please insert disk", and if this message occurred the owner was instructed to repair the system. This is an NDEV Menu error message displayed when there is no inserted disk (real or emulated).
The Wii Fun Centre (UK version of the Fun Center) had an "HD TV, Blu-ray player, a Nintendo Wii with four Wii Remotes, Wii Nunchuk and Wii Wheels, a Balance Board, four Nintendo DSi consoles and a library of films and games". Thus, it is the ultimate version, especially because it came with 4 DSis. It was released in March 2011, right around the release time of the 3DS.
We don't have the firmware or much internal info on how the Wii Fun Center worked. Because of that, it's one of our Holy Grails.