The RetroN 3 gaming system tries to do it all. There's three cartridge slots in this 3-in-1 system: Super Nintendo, NES, and Sega Genesis. And on three of the four sides of the system you'll find a set of two ports for each system's original controllers. If you don't have any of those original controllers, you can play games on the included wireless controllers, which look to be total rip-offs of the six-button Sega Genesis controller. Nice!
A three-way switch on the front lets you select which "system" you want to play. I love that you could have it loaded up with three different games and then just switch between them.