TheSmartAss.info's suite of Java emulators allows smooth, in-browser playback of literally thousands of old-school video games: 517 Atari titles, 148 for DOS, 636 Game Boy games (and 410 for Game Boy Color), 2,019 (!) NES titles, 238 GameGear games, 802 Sega Genesis titles, and 284 for the Sega Master System. Highlights include Space Invaders, Frogger, Galaga, Pitfall!, Super Mario Bros., The Legend of Zelda, Metroid, SimCity, Zero Wing, Duke Nukem, Sonic the Hedgehog, Aladdin, Earthworm Jim, Pokemon, and Metal Gear Solid. Use the search function to find your favorites! You can also register an account to save games on emulators that support it. Make sure to check the purple bar below each game for control info and links to alternate emulators in case the default one is buggy or slow.
posted by Rhaomi on Nov 30, 2009 - 54 comments

JNES is a Javascript Nintendo Emulator. It works shockingly well.
posted by chunking express on Sep 18, 2009 - 46 comments

Play 666 Nintendo games in your browser with Virtual NES. (some suggestions of the best games) It joins the extensive EveryVideoGame , the slow GameBoy Online, and the beloved Virtual Apple. [prev. and prev.]
posted by blahblahblah on Nov 6, 2007 - 37 comments

Mario Adventure - SMB3 hacked into an entirely new high-quality game
posted by Protocols of the Elders of Awesome on Feb 17, 2006 - 20 comments