Artificial systems with perceptual capabilities and robotic systems in general are complex combinations of mechanical and electronic parts that operate through the coordinated activation of perceptual capabilities, control strategies and learning techniques. All of these components have to be appropriately integrated in a common framework. The effectiveness of each of the subsystems cannot be fully assessed in isolation. This is because the success of the overall system does not depend on the quality of the constituent elements only, but also on their appropriate integration and on the characteristics of the interaction of the resulting system with the environment. Integration in this context is an important problem per se since it has to cope with considerable complexity and, in many cases, with scarce resources and conflicting requirements. For this reason, a lot of effort has been devoted to the development of integrated prototype systems and demonstrators. The importance of such prototypes is twofold; Firstly, they act as test-beds for evaluating the true effectiveness and robustness of their constituent components. Secondly, each of these prototypes addresses the needs of important application areas. Four such prototypes that have been achieved at CVRL are briefly described below. These research prototypes have been successfully tested and validated through extensive user trials at a national but also international level. Moreover, they have attracted the interest of the general public, through the extensive coverage they got in the national and international press and other media.