Vimeo user Andrej Kyselica got himself a set of GE-35 christmas lights. The main characteristic is each bulb on the light chain is individually addressable, through the Fez's SPI capability for high-speed communication. Then, he used Microsoft Lync dev kit. Finally, he wrote the names of his IM contact list on post-it papers and tagged each bulb to indicate an individual. Each bulb will change color according to the state of the user that corresponds to, red for offline, green for online, yellow for away etc. Read more here.