I just learned about an interesting "citizen science" project that anyone can join. GLOBE at Night 2008 aims to measure light pollution by collecting simple observational reports on the visibility of the constellation Orion from people all over the world between February 25 and March 8. You can download observation packets with reference sky charts and observation sheets from the GLOBE site. This can be a simple but educational and useful observation activity for families or classrooms, and the data will help us to better understand the extent of light pollution world-wide. As the web site says:
Come join us for the 2008 GLOBE at Night Campaign from 25 February - 8 March. 2008 marks a monumental shift in human history when more than half the people on Earth are expected to be living in cities. Because of the ambient light of urban landscapes, many city dwellers have never seen a sky full of stars.