OpenLaszlo

OpenLaszlo was one of the earliest commercial RIA platforms in the market, and one of the first to come out with a programming language optimized for building highly interactive rich Internet applications: the LZX language.

Started by Laszlo Systems as a commercial product under the name Laszlo Presentation Server (Relase 1.0 in 2003), the platform was open sourced and renamed into OpenLaszlo server in October 2004. Since then the product has been downloaded more than 600,000 times and OpenLaszlo has been adopted in more 25 countries by companies like IBM, Walmart, HP, Alcatel-Lucent, H&R Block, Monster.com and many others.

OpenLaszlo not only supports the generation of Flash8 and Flash9 applications, but has Ajax/DHTML support as well, meaning you can run the same application on as different platforms as the various JavaScript engines in Firefox, Safari, Webkit and IE as well Adobe Virtual Machine 1 (ActionScript2/Flash8) and Adobe Virtual Machine 2 (ActioinScript3/Flash9).

I've used OpenLaszlo in various projects in the last 5 years, and the technology has never failed me. LZX is the most fun language to build RIAs with, and has a lot more flexibility than ActionScript3 or pure JavaScript development.