The MPEG-2 standard has allowed Digital Television to become a reality at reasonable costs. The introduction of MPEG-4 will allow content and service providers to enrich MPEG-2 content with new 2D and 3D scenes capable of a high degree of interactivity even in broadcast environments. While ensuring compatibility with existing terminals, the user of the new terminal will be provided with other applications, such as Electronic Program Guides, Advanced Teletext, but also a new non-intrusive kind of advertisements. For these reasons, a scalable device opened both to the consolidated past (MPEG-2) and to the incoming future (MPEG-4) is considered a key issue for the delivery of new services. The presence of a Java Virtual Machine and a set of standard APIs is foreseen in the current terminal architecture, to give extended programmatic capabilities to content creators. This paper covers the application areas, the design and the implementation of a prototype for this terminal, which has been developed in the context of the ACTS SOMMIT project.