Body-based interaction constitutes a very intuitive way for humans to communicate with their environment but also among themselves. Nowadays, various technological solutions allow for fast and robust, noninstrumented body tracking at various levels of granularity and sophistication. This chapter studies three distinct cases showcasing different representative approaches of employing body-based interaction for the creation of public systems, in two application domains: culture and marketing. The first case is a room-sized exhibit at an archeological museum, where multiple visitors concurrently interact with a large wall projection through their position in space, as well as through the path they follow. The second example is an ''advergame'' used as a means of enhancing the outdoor advertising campaign of a food company. In this case, players interact with the wall-projected game world through a virtual, two-dimensional shadow of their body. Finally, the third case presents a public system for exploring timelines in both two and three dimensions that supports detailed body tracking in combination with single-hand, two-hands, and leg gestures. Design considerations are provided for each case, including related benefits and shortcomings. Additionally, findings stemming from user-based evaluations and field observations on the actual use of these systems are presented, along with pointers to potential improvements and upcoming challenges.