Back at MAX I raved about Thermo, a new product being developed by Adobe. It basically allows designers to create Flex mockups/prototypes that actually have some dynamic power to them. It really blew me away (and made me wish, once again, I was doing more Flex work). Adobe Edge's newsletter has a video on Thermo so you can see it in action:
The Edge is actually a pretty cool newsletter. I keep forgetting to check it out. If you haven't seen it before you should spend some time checking it out.