1. SDLMAME (SDL version of MAME (Multiple Arcade Machine Emulator); edit the Makefile to set the operating system then compile; run mame -createconfig and edit mame.ini if needed, then move it to ~/.mame/).
2. A 15GB torrent of all the arcade ROMS for MAME.
3. The history.dat, cheat.dat, hiscore.dat, mameinfo.dat, icons, artwork and samples. There are images of flyers, marquees, cabinets, background images and snapshots as well, if desired.
4. Wah!cade (front-end to M.A.M.E.; run wahcade-setup first - set the MAME executable to cd to the mame directory then run the executable; add -cheat to the command line options).
5. Run wahcade, choose the game, press 1 to launch it. Keys: 5 to insert a coin; 1 to start a game; Ctrl-F10 to toggle OpenGL rendering, which massively improves some games; tab for options, including enabling cheats (infinite lives).