In January, a website called "wonderfl" was launched. It's a very fast web interface for the Flash compiler. Type some code in the window and after a moment of inactivity it will compile and run your Flash program. I think it's pretty awesome.
http://wonderfl.kayac.com/Kenta Cho has created a bunch of very small games at wonderfl. Check them out and play with their source code at:
http://wonderfl.kayac.com/user/ABA/codesI have been browsing the website and making a list of awesome visual demos here:
http://wonderfl.kayac.com/user/shaktool/favoritesOr check out my own posted codes for some heightmap renders.
Complaints:
-no code auto completion or hinting or anything like that.
-it's not clear what license the code is available under. The implication is that it's something like Creative Commons with derivatives allowed, since it encourages you to "fork" whatever code strikes your fancy, but it's not explicitly stated anywhere. Some people will put some sort of license in a comment inside their code, but that's rare.
-The thumbnail generator is buggy.
-When browsing for codes, the sorting options are very limited.