we have a rainbow that creeps through the house every sunny day. we lucked out and a previous owner of our house was a carpenter and installed all sorts of awesome things to make the house unique. there are two beveled glass windows, one on the porch and one in between the living and dining rooms. sunlight passes through the glass window on the porch, which acts like a prism, and casts a rainbow that creeps across the floor and onto the wall.
now here is where i'll really nerd it up. do you know why prisms create rainbows? well white light is made up of all colors of light. as the light passes through the glass it slows down (refracts) and slightly changes direction. each color, or component of the white light, passes through at a different speed and so when it exits the glass, it is separated into it's components, or colors. i suddenly feel the urge to listen to some pink floyd, dark side of the moon.