OpenLaszlo "Legals"
Laszlo has struggled a bit in the past with what they were going to be, most recently moving to open source, and it will be interesting to see how this move pans out. With the release of Flex 2 (write up coming soon), they're no longer the only commercial product in the game. But if they can take advantage of the rise in popularity of Ajax and DHTML then they will have a unique niche.
My only concern is that by incorporating so many different technologies they will lose some focus and their individual implementations will suffer. There is a lot of room for this type of RIA implementation, and I think OpenLaszlo has it covered. What may happen is Ajax developers will be drawn to OpenLaszlo and then move to other technologies as their needs change.
They're providing the current release of Legals over at the Legals page and they have a FAQ for those interested in getting more information.