The one that really grabbed me was 'The Internet of Arduino' ~ http://arduino.cc/blog/?p=117 http://arduino.cc/blog/?p=117 An Ethernet shield for Arduino from t

The one that really grabbed me was 'The Internet of Arduino' ~ http://arduino.cc/blog/?p=117 http://arduino.cc/blog/?p=117 An Ethernet shield for Arduino from the blog, where I got the link. You can get wireless boards ~ http://www.ladyada.net/make/xbee/arduino.html http://www.ladyada.net/make/xbee/arduino.html but the cost. Now you have the possibility of really wiring in lots of very cheap programmable Internet sensors using cheap Cat5.