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.
Children review classic games- some more. Back in November '03, 1up.com rounded up some kids from the 8-12 age range and had them play video and arcade games from the 70's and 80's, including Pong, Donkey Kong, and Tetris. The resulting commentary was mostly along the lines of "Tim: They could've just as easily called this game anything—Baseball, Bowling, Escape From the Monsters. EGM: Did you score? Kirk: I bumped into a dot." In December 2004 they brought them back to review Mike Tyson's Punch-Out and the 1983 Arcade version of Star Wars, among others. "EGM: What do those TIE Fighters look like? ...Are they scary? Anthony: No. It feels like they're trying to give me flowers."
EveryVideogame.com... many retro videogames (arcade, nintendo, gameboy, sega) available for online play via a java applet.