A resistor colour code mnemonic.

# Colour - Mnemonic
1 Brown -- Boys
2 Red ---- Rape
3 Orange - Our
4 Yellow - Young
5 Green -- Girls
6 Blue --- But
7 Violet - Violet
8 Grey --- Gives
9 White -- Willingly

Not covered by this mnemonic are gold and silver which are used to indicate multipliers of 0.1 and 0.01 respectively.

Update: April 12, 2000

Thank you bitter engineer for the 'Get Some Now' part of the mnemonic. Tolerance bands (or lack thereof) are addressed in the tolerance band code node.

Actually, you append Get Some Now to the end of the mnemonic to remember gold, silver, and none. When used in this way that they do not indicate negative exponents, but instead the accuracy of the resistor: gold = 5%, silver = 10%, and none = 20%.

During World War II, there was a variant of this mnemonic that was more suitable for racist children: Black Bastards Rape our Young Girls Behind Victory Garden Walls.

My personal favourite Mnemonic for Resistor Colour Codes is similar:

# Colour --- Mnemonic
1 Brown ---- Boys
2 Red ------ Rape
3 Orange --- Our
4 Yellow --- Young
5 Green ---- Girls
6 Blue ----- But
7 Violet --- Virgins
8 Grey ----- Go
9 White ---- Without
5% Gold ---- Get
10% Silver - Some
20% None --- Now

Clearly, I didn't learn this in school. School prefers things like "Bye Bye Rosie Off You Go (to) Birmingham Via Great Western". That isn't very memorable though...

This is my favorite mnemonic for remembering resistor color codes, because it solves the problem that black, brown, and blue all start with the letter B. The second letter of each B-word in the mnemonic corresponds to the third letter of the appropriate color.