An interactive play set is described which comprises one or more active physical play pieces. In an embodiment, each active physical play piece receives data from one or more other play pieces in the play set and uses this data to generate proximity data. The proximity data describes distances between two or more play pieces from which it receives data to three or more proximity levels. The proximity data is then transmitted to an interactive entertainment experience (such as a game) which reflects changes in proximity level. For example, the changes may be visible in a graphical user interface or another play piece or audible to a user.