The new generation of television viewers is currently being confronted and becoming acquainted with a series of technological developments in the realm of consumer electronics and gaming that raise their expectations for similar advances in TV broadcasts. The MELISA platform aims at the cross-media broadcasting of sports events featuring interactive advertising and sports-related games over digital television and next generation mobile network infrastructures. The platform provides services for optimal presentation of complex interactive real time video content, for advertisement and an advanced real-time gaming (betting) engine in at least two different client platforms. User interface design is a major issue in a complex end-to-end solution having to cater the needs of users ranging from broadcasting professionals to end-users. Especially in the case of interactive gaming there are numerous challenges in the user interface design, in order to deliver to all categories of devices (and end users) equal quantity and quality of information. In this paper we present the overall system architecture and philosophy and then focus on user interface design issues both for the routine work of broadcasting professionals as well as the end users, owners of different types of consumer devices (such as PDAs and interactive TV Set Top Boxes).