Mathalicious' iPod dPreciation at the start of class.
Students marveled that the original ipod was about as old as they are. They waffled on which they thought might depreciate more quickly - the Nano or Touch. And they struggled with what in their world might actually "appreciate" in value!
If you haven't been to the Mathalicious site since they updated it, you should go. there. now! I love the organization, the integration of Desmos, and the clarity/ease for teaching!