Open source, no-plugin, rich GUIs for the Web

Lazlo does was Java was supposed to do -- let you run desktop-app-like applications within a browser window. But Laszlo doesn't require any plugin on its own, or flaky, slow Java. Instead, the Laszlo compiler turns Lazlo code (which is written in very fast, flexible, human-readable XML) into Flash apps. Pretty much everyone has Flash installed, so users can run your apps without installing new software (but since the Lazlo code is compiled down to Flash, it could also be compiled down to something else -- IOW, if Macromedia gets to rank with you, you could compile your apps to Java, to C++, Mono or whatever)."