Programming may benefit much from a theory named the Algebra of Communicating Processes (ACP). This brings ease and fun to event-handling and concurrency.
We have created a Scala language extension with features from ACP, by the name of SubScript. As an example we present a simple GUI controller written in SubScript, and show some quick extensions. Then we briefly touch our current implementation work: a data flow construct and support for actor programming.
The SubScript implementation is an open source project. It is fairly simple and efficient; a SubScript executor maintains a "call graph", and it does not rely on threading and polling.
There is still much work to do, and a lot of ACP-related programming patterns are to be discovered.
For more information see http://www.subscript-lang.org.