Abnormal Lenses

There are a lot of really nice lenses out there, but there also are a lot of things that aren't "normal" camera lenses in any sense of the word. They may be special-purpose lenses (fisheye, soft-focus, telescope, microscope, etc.), door peepholes, pinholes and zone plates, mirrored stuff, various plastic or glass objects, water, etc. Use one. Digital imaging makes it easy to see and creatively manipulate the somewhat unpredictable effects of such optics.