Levitated, is a Flash art and design organization based in Albuquerque, New Mexico. The work that they do is released as open source code, and is some of the most interesting interactive art I've seen done with Flash. In their own words:

Levitated.net contains visual poetry and science fun narrated in an object oriented graphic environment.

The sketches and applications generated as a byproduct of research are provided online as open source Flash modules.

These pages are attempting to fasten a usable structure around a continually evolving computational ecology, so that it may be observed and enjoyed by participants of the network.

More formal code and design ideas are periodically published as tangible commodities in book, paper, and printed form.

Some of the interactions are relatively abstract, some are a bit more representational. Sea Thing, is one of my favorites. It's a loosely connected set of individually aware objects that function as an entire organism. When clicked, they separate from the giant mass.