I am excited to hear that Laszlo has been released under an open source license:
The Laszlo platform is free and licensed under the Common Public License, version 1.0. Commercial and non-commercial users are encouraged to use, extend and modify the Laszlo platform to suit their needs within the terms of the license.
Laszlo uses Flash as a rendering engine but does not use the Flash object model. Theoretically, some other completely free rendering engine could be used.
Before this there hasn’t really been an open source, rich internet application platform. Well, except for the ol’ DHTML work-horse that has been persistently trying to fill in some of the rich internet app vacuum.