Puppy Arcade is a Live CD image that can be played on almost any computer using any operating system. It contains emulators for the following systems: Amiga (500, 1000, 2000), Apple (68k, 128k, 512k, SE, MacOS, Plus), Atari (ST, 800, 800XL, 130XE, 5200), Amstrad (CPC, Plus, VEB), Arcades, Colecovision, Commodore (64, 128, VIC20, PET), Doom, GameBoys (GB, GBC, GBA), GameGear, Genesis/MegaDrive, MasterSystem, MS DOS, MSX, N64, NDS, NeoGeo, NeoGeo CD, NES/Famicom, PC Engine/TurboGrafix, PSX, ScummVM, SNES and ZX Spectrum (16k, 48k, 128k, +2, +2A, +3) and more! Visit the official website for more information and tutorials.

Dreamcast, PS2, Saturn, Gamecube emulators (and others) available here, or here.

There are a couple releases for older hardware available at the Puppy Arcade Website.