From Wikipedia:
OpenLaszlo is an open source rich Internet application framework developed by Laszlo Systems Inc.. The OpenLaszlo server compiles programs written in the LZX language (a mixture of XML tags and JavaScript) into either DHTML (commonly known as AJAX now) or Adobe Flash bytecode, currently supporting Flash7 and Flash8. The server - which originally was a proprietary software - was open sourced in October 2004 under the Common Public License. OpenLaszlo is the only rich Internet application platform which is capable of compiling into two different runtimes from the same code base.