Wii Virtual Console

Brand: Various Developers, Licensed by Nintendo

Product: Wii Virtual Console games (see further description on Wikipedia)

Summary: Download classic games from the NES, SNES, Sega Master System, Genesis, Turbo Grafix 16, N64, and other "obsolete" systems. While the technology may be outdated, the games are still classic (due to nostalgia or timelessness). Requires a purchase of Wii Points, either in Wii 2000 Points Card form or directly from your Wii.

Price: Between $5 and $20 or so dollars, in Wii Points. The Wii 2000 Points Card costs about $20.

Obviously: Requires a Wii. Some games may require the Wii Classic Controller peripheral (price: about $20).