Ghost Imaging

Quantum effects are sometimes very strange and occasionally even useful. Ghost imaging is a particularly bizarre example. It's possible to create an image using pairs of photons. One photon is sent to the subject and the other is sent to the camera. An image of the subject is created using the photon which is received by the camera - even though that photon was never anywhere near the subject! This is possible because of the (weird) quantum nature of photons. Here's a blog post that discusses recent research in which the photon source is classical instead of quantum - supposedly you can even use sunlight. Making ghost images by getting sunlight to act quantum