Fabrice Bellard has written an impressive PC emulator that actually emulates a PC with a 32 bit x86 compatible CPU. This is some really imaginative use of pure JavaScript which I’m sure no-one would have every dreamed of as it allows you to run a virtual instance of Linux inside a browser window!
It currently only works in Google Chrome 11 or Firefox 4 as it uses part of the WebGL HTML5 spec that Safari hasn’t implemented yet but is definitely worth playing around with. You can even compile C files!
