This demo presents the Musical Ensemble Management System (MEMS) developed for the ITP4507 Contemporary Topics in Software Engineering module. It demonstrates how the system manages music ensembles and musicians through features such as creating ensembles, selecting the current ensemble, adding, modifying, and deleting musicians, displaying ensemble details, and using undo and redo functions. The system is designed with the Open-Closed Principle and uses the Command, Factory/Abstract Factory, and Memento design patterns to support future expansion to other ensemble types.