MacMAME has been called "...a masterpiece of arcade emulation..." and I have to agree. MacMAME is the Macintosh version of the Multi-Arcade Machine Emulator [MAME] and is, in my opinion, one of the greatest little apps ever created. It allows your Mac to emulate old coin-operated arcade machines so that you can play literally thousands of games.

The emulator is free to download — the author suggests that if you keep it you donate $10 to a charity. Believe me, get the checkbook ready, if you've ever spent more than three quarters at an arcade you'll be keeping this program. MacMAME is constantly being refined — you'll see a new version every few months — to support more games or fix little audio glitches in a certain game.

Once you download the emulator, you only need to download some ROMs — the memory dumps of the actual game itself — and Bob's your uncle.

You'll laugh... at games you thought you must have have only imagined...
[for instance, who can believe that the game Chiller was actually produced — in 1986, no less]
You'll cry... at the number of quarters you wasted...
You'll pick up a badger at the petting zoo... and kiss him full on the lips because someone slipped something into your coffee at work...
Then you'll do a little dance, make a little love, and then get down a week from Thursday.

If you have a Mac and know what the "pie factory" was in Donkey Kong you need to download MacMAME... play that game you only saw once. You know... that game that was at the gas station by your uncles house. That summer in '84 when you went everywhere in that damn Ghostbusters tee shirt you were so proud of.

The current version of MacMAME requires a PowerMac, however an older 68K version is still available. The official site for MacMAME is: http://macmame.org/

Note: Various URLs for MAME resources are listed on the MAME node (the same ROMs will work on both Mac and PC) so I haven't included them here. There is some cool (if not updated recently) info about how to make the most of MacMAME archived (via archive.org) at http://web.archive.org/web/20011101221730/http://homepage.mac.com/marvyn/mame/.
For those wondering, the "pie factory" was usually the 8th level of Donkey Kong — a level my quarters seldom witnessed. It featured little pie-like trays of dirt (?) on conveyer belts... hence the nickname.