Martin Mander recently noticed that his back garden attracted bats. Inspired by this, he set about creating a camera that could see in the dark and take pictures of the bats as they came flying in. He repurposed a hand-held drill to provide power and added IR LEDs to illuminate the field of view. He used, of course, a Pi NoIR camera to take the footage. You can read more, and imitate his project, by viewing this Instructable.