During the first Arduino week, I also worked in group with Benoit and we came up with this 1 and 1/2 day project : Fortune teller.
It is a do it yourself fortune teller machine. If you knock on the box with the magic wand, you have 5 seconds to swap the wand and help the machine to predict your future. The wand a temperature sensor that trigger the display.
Here you can see a video: