Apache ODE, as in “Apache Orchestration Director Engine” (wow thats a mouthful), is a Top Level Project under the aegis of the Apache Software Foundation.
The stated objective of the ODE is “to create a reliable, compact, and embeddable component capable of managing the execution of long-running business processes defined using the BPEL process description language“, and the focus has been on “developing small modules with minimal dependencies that could be assembled (and easily reassembled) to construct a full featured BPMS“. LEGO blocks of BPMS?