This document provides information about a practical session on building ontology-based web services. The session is part of a larger tutorial on ontology engineering and lexical semantics. Students will work in groups of three to model a governmental service and its processes. They will build web services for each sub-process and publish the WSDL of the services using terms that are defined in the Palestinian government ontology (Zinnar). Students can reuse services built by other groups. The goal is to implement an interoperable governmental service using standardized ontology terms.