I wrote a long time ago about my love to my first computer (all geeks have this :) ), Commodore 64. I’m still playing sometimes on Frodo in Kennedy Approach… I don’t need another simulator, but this….
http://phpc64.extra.hu/ is C-64 simulator written in PHP and accessible via browser… It is not very functional (it has 10kb in PHP and HTML code, so it seams to small) and I did not tested it, but it allows to run simple BASIC programs (of course You wont be able to run binaries, like Frodo can).
It recollects me other nice piece of work – UNIX-like system written in Java Script. Fully functional!
http://www.masswerk.at/jsuix/