DICE is the "Discrete Integrated Circuit Emulator." It emulates game systems that lack any type of CPU, consisting only of discrete logic components. With it you can play software-based recreations of hardware-based games. All the games are designed around the original schematics.
DICE currently supports Crossfire; Clean Sweep; Wipe Out; Pin Pong; Crash 'N Score; Jet Fighter; Quadrapong; Shark JAWS; Anti-Aircraft; Exidy Attack; Breakout; Midway TV Basketball; Stunt Cycle; Pong Doubles; Gotcha; Space Race; Pong; and Rebound.
DICE blog
DICE downloads (including source code)