These days, emulation makes having old school consoles hooked up to your TV pretty unnecessary. But if you must play Chrono Trigger from the original cartridge, the RetroN 3 is a pretty great way to do it.
In addition to having three cartridge slots for NES, SNES and Genesis games, respectively, it also has ports for all three systems' original controllers. If you don't have any kicking around, it comes with two generic wireless controllers.
But really, if you've got stacks of old cartridges and want to have one system plugged into your TV instead of three, this is a pretty sweet solution. It's available now for a mere $70. [HyperKin via Gadget Review via Oh Gizmo! via Gadget Lab]