If you don't want to rely on an obscene/racist mnemonic to help you figure out the value of resistors based on their colored bands, you can make this nifty papercraft resistor decoder from Adafruit.
It’s the newest tool in our Circuit Playground -- when you can’t get to your iPhone or iPad, use paper! One side helps you read 4-band types and the other side takes care of 5-band types. The Resistor Helper is on Thingiverse as a PDF (with Illustrator editability preserved). Designed by Adafruit with Matthew Borgatti.Resistor Helper – Papercraft Resistor Calculator
Mark Frauenfelder is the founder of Boing Boing and the editor-in-chief of MAKE and Cool Tools. Twitter: @frauenfelder. His new book is Maker Dad: Lunch Box Guitars, Antigravity Jars, and 22 Other Incredibly Cool Father-Daughter DIY Projects