In the past few years, we have covered a bunch of Raspberry Pi powered arcade machines. RealMagicman03 has built one with about 1000 LEGO pieces. It has a SNES style controller, 3.5″ HDMI display and can run many old, classic games.
According to the maker, this system can build Atari 2600 to PSP games. You can find out more about it on Reddit.