Syncope needs a new workflow engine, for many good reasons: here's why I've started playing around with Activiti. Activiti looks really interesting because of features and Apache 2.0 license; moreover, its spicy story makes it even more attractive.
Unfortunately, the documentation is fully Eclipse and ANT oriented: this sounds a bit cumbersome for people (like me, of course) used to be in love with Maven and quite allergic to the dark (hem, let's say, more in love with everything that used to be connected to the Sun).
Anyway, Activiti team did not forget completely the rest of us and is regularly publishing artifacts to Alfresco's repository.
Hence, I've downloaded the latest 5.7 version, got the source code examples, and wrote a simple multi-module Maven project, able to compile and run all tests defined. Source code is available at GitHub.