libavg is a very interesting package for multimedia installations:
libavg is a high-level multimedia platform with a focus on interactive installations. It is meant to pick up where Macromedia Director leaves off and gives you high-quality hardware-accelerated visuals as well as easy and flexible authoring, testing and deployment. libavg integrates well with other open-source solutions for sound, networking and hardware device support, resulting in a complete and well-integrated package. It uses an xml-based layout language for screen design and python as scripting language.
libavg aims to replace Macromedia Flash or Macromedia Director with following design goals: high-quality visuals, high-quality sound, quick authoring, support for a broad range of systems and openness for expansion (see also the features page for details).
And best of all: it uses Python, which is a clean, simple, fast and easy to learn object-oriented scripting language.