In this paper we introduce EventAware, a context-aware mobile recommender system to personalize the agenda of users attending to a congress. In particular, we first introduce the EventAware system, which includes an intuitive user interface with an attractive design to enhance user experience. EventAware incorporates some implicit contextual information, automatically initializes both the user's profiles with minimal user interaction and the properties of the items, and it uses a context-aware tag-based recommender algorithm. EventAware has been specifically crafted to assist attending users to a congress by providing them with smart and personalized sessions and exhibitors during the congress. We demonstrate its usability through a live-user case-study in one of the biggest events of mobile technology in the world, held in Barcelona.