I recently heard about GAIA - a new framework for creating Flash applications and thought I'd check it out. I haven't had time to use it extensively at all yet, but so far I'm very impressed with what I've seen - it's small and lightweight, and doesn't appear to try and do too much for you (unlike some of the other frameworks out there). It also has a very simple API and an easy to use panel in the flash authoring environment. My biggest complaint so far is that there's no Flex Builder version of the panel. GAIA creates a scaffolding driven rapid development environment and allows you to make use of the timeline or pure AS for navigation tweening.
Whether you decide to use GAIA in production or not, one thing is for sure: it certainly makes the process of creating Flash prototypes for clients as quick and painless as possible. If you build RIAs, I strongly suggest visiting the GAIA website at
http://www.gaiaflashframework.com/ and taking a look for yourself.
I'm trying to do as much as I can to help there because I think it has great potential. And I also wanted your feelings on Railo going JBOSS. Drop me a line if you get the time. Thanks!