Service oriented computing is an emerging paradigm for programming distributed applications based on services. Services are simple software elements that supply their functionalities by exhibiting their interfaces and that can be invoked by exploiting simple communication primitives. The emerging mechanism exploited in service oriented computing for composing services –in order to provide more complex functionalities– is by means of orchestrators. An orchestrator is able to invoke and coordinate other services by exploiting typical workflow patterns such as parallel composition, sequencing and choices. I'll present JOLIE, an interpreter and engine for orchestration programs. The main novelties of JOLIE are that it provides an easy to use development environment (because it supports a more programmer friendly C/Java-like syntax instead of an XML-based syntax) and it is based on a solid mathematical underlying model.