Back when I was in southern Ontario, I met a ham on the air who told me a rhyme he used to memorize the resistor colour codes. An interesting thing about the hobby of ham radio is that you meet some amazing people who have been working with radio and electronics for decades. I remember tales of a fellow buying his first transistor to play with, in the 60s, for $75. A princely sum even now. This rhyme goes back at least to the 60s, and may be even older than that. Those with particularily delicate sensibilities may be offended. The rhyme, and it's explanation, after the jump.
Right then, glad you're still with me :)
The rhyme is thus: Bad Boys Rape Our Young Girls, But Violet Goes Willingly. This translates to black, brown, red, orange, yellow, green, blue, violet, gold, white. They increase from 0 to 9, and then in powers of ten. On average, there will be three or four bands - the last one is gold or white and will be the tolerance. If we find a resistor that is yellow, violet, brown, we go through our rhyme. Yellow is the fifth word, but since we are counting from zero, it means four. Violet is seven, and brown is 1. So we have 47 * 10^1, or 470 ohms.