So the good people at the The Internet Archive (archive.org) have put up some 900 arcade games from the 1980s (techcrunch.com) - playable within your browser so long as you have Java enabled (it utilizes the 'almost but not quite ready for prime time JSMESS' emulator - which is essentially a JAVASCRIPT/JAVA port of MAME).
So far, I've played Mat Mania, Elevator Action, Mr. Do and Yie-Ar Kung Fu. It's really hit and miss. I've yet to get sound for anything, and the controls are... well, they can range from 'great to 'downright frustrating' (Mat Mania was *almost* unplayable, Mr. Do was playable when not a little glitchy, but I actually got up to Chain with two 'Perfects' on Yie-Ar Kung Fu - so take *that* Northwood Pizza arcade room).
Still, this should only improve over time and it's pretty awesome to see a lot of games, on which I dropped serious childhood money, playable for free online.
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