We have a hard time imagining exactly what circumstances would best enable you to enjoy this Magic Showerhead with Color Changing LED ($55). Powered only by water pressure - no batteries! - this high-tech device switches between red, green, and blue LED lights every two minutes. The manufacturers say that this is a great way of encouraging people to take shorter showers. We're betting that in actuality it would make them longer, since in order to notice your watery disco party, you'd have to be washing yourself in the dark.
But then, there is one good reason we can think of for showering in the dark... and color-changing disco lights would make that even more fun than it is already.