Mike Thompson's "Blood Lamp" is a single-use lantern that draws its energy from a drop of your blood, making you consider the cost of energy in a uniquely personal way.
For the lamp to work one breaks the top off, dissolves the tablet, and uses their own blood to power a simple light. By creating a lamp that can only be used once, the user must consider when light is needed the most, forcing them to rethink how wasteful they are with energy, and how precious it is.
(via Cribcandy)