Years ago, a friend of mine was taken on a bar crawl for her birthday. They 'forced' her to "Drink the Rainbow." At each bar she had to drink a beverage/cocktail matching a color in the rainbow: Red, Orange. Yellow, Green, Blue, Indigo, Violet. (If you are hard core, you can toss in infraded and ultraviolet, infrared being black and ultraviolet being white or clear.) You know, Bloody Mary, Screwdriver, something yellow (a Greyhound?), Grasshopper, etc. If I remember correctly she only made it through green.
This wonderful needle point from Craft made me think of it.