by Matej Blagšič @ instructables.com:
Recently I attended a course in our University of Electrical Engineering and we were making ourselves a small weather station. It included learning about soldering, sensors and arduino. It was super fun making it with little kids and other high school kids my age. I will show you how you can build it yourself, what components do you need and explain you the code and how can you upgrade it with more sensors.
DIY Weather Station with Bluetooth – [Link]