OpenWFE: "OpenWFE means Open source WorkFlow Engine.
This engine is implemented in Java. It is available under a revised BSD licence.
OpenWFE not only features a workflow engine, but also a full Business Process Management Suite.
As released, it features a Worklist component for storing workitems (tasks) for participants and a Reactor component, for automatic participants.
It also features Droflo, a web based flow designer.
OpenWFE doesn't require any Application Server, just a 1.4.x Java Development Kit.
OpenWFE-dotnet is a C# written library for people developing on the .NET platform. It allows them to access an OpenWFE REST worklist to participate or a launch a flow."