Take your smartphone and hold it as close as possible to a box with beads. While trying to focus with the camera, you will get beautifully blurred, circular light reflections. The best results can be achieved with glass beads (e.g. rocailles) under artificial light.
More photos:
http://fotos.blaustern.bplaced.net
Photo of big multi-colored beads
Photo of small blue beads
Photo of small Brown beads
