Roy G. Biv

A mnemonic used to help you remember the order of colors in a rainbow, which is also the order of the colors when sorted by wavelength (which would be the inverse of frequency)

From long wavelength:

• Red
• Orange
• Yellow
• Green
• Blue
• Indigo
• Violet

Also apparently conforms to the color code of resistors when ordered by their resistance, with the addition of black before red, and grey and white after violet.

This mnemonic for colors is in use in English edition of Paranoia RPG. In the game, remembering the correct order is not only essential... it's mandatory, due to the fact that it's also the order of the security clearances.

Of course, you also need to remember where infrared and ultraviolet are on the spectrum, but that's easy.

(I think there was also someone called Roy-G-BIV as a mentor for the new troubleshooters in the 5th Edition...)

In Finnish edition, the mnemonic is Poke V. Siili (Something like "Receptionist V. Hedgehog"), coming from:

Punainen
oranssi
keltainen
vihreä
sininen
indigo
lila

(From the "(Mandatorily) Happy Guys in Jumpsuits of All Colors of Spectrum" department =)