I'm giving a workshop on extending Arduino with shift registers and multiplexers, collecting the data in Pd, on the 14th and 15th of December, in Athens, Greece. More info here (in Greek only, sorry...) http://www.frowntails.com/technology/arduino-extended/

Here's the English version of the workshop webpage http://www.frowntails.com/en/technology_en/arduino-extended/