I just released Wombat a couple of days ago -> An open source (Boost software license), header only API, written in c++11, that lets you "paint" in code and execute a finite state machine (DFA), using a domain embedded specific language.
Some notable features -
0. The queue can be extended in RT.
1. Lambda expressions are used as semantic actions.
2. There is also support for non-orthogonal persistence.
3. Events are generic ! you can even use Kinect gestures as input !!
Edited by Eliad Moshe, 10 September 2013 - 04:34 AM.