Making a pinhole camera can be as simple as punching a hole in a piece of paper: The sun projects through the gap to throw an image onto another surface (like a second sheet of paper). By adjusting the position of the pinhole, you can focus the image, although you can't exactly get an HD picture. Turning a cardboard box that fits over your head into a pinhole projector will reduce light interference and give you a better closeup, but that's not an experience you can share with your friends.