Here is a good idea made just right. The Lumen Tree by Adam Frank is an oil lamp that projects the shadow of a tree onto your wall. The tree and the body of the lamp are made of acid-etched stainless steel, and (this is cool) the flame comes from a 17-hour liquid wax fuel cell, which is both odorless and clean-burning. As the flame flickers, the shadow moves naturally, and – if you’ve forgotten elementary math – the farther away from the wall you place the lamp, the larger the shadow will be.
Adam Frank is a product designer and inventor who focuses largely on investigations into the nature and possibility of using light in design. He began his work with a high-tech theater company in San Francisco and has since become internationally recognized for his ingenuity. He’s got a number of other truly awesome inventions and installations, which can be seen at his website. (And of course you can purchase the Lumen online through his site.)