nucular is an easy to use reactor inspired by EventMachine.
You can find some examples in the examples/ directory.
I know many hate AGPL, especially in libraries, but I hereby give permission to use the library for network related services with any license you see fit, as long as you give back changes to the actual library.
What I mean is, if you just use the library and the already implemented protocols to implement some kind of service, you don't have to put your service under AGPL, but if you make changes to the already implemented protocols or internals of the library, I want those changes back.