A long long time ago in a previous life I was studying for a City & Guilds in Radio TV & Electronics Servicing at college.
Sadly, about the only thing I remember from those days is how to interpret the meaning of the coloured bands on resistors so that you can tell their rating (see the feet and hands in the photo). The colours are Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey, White, and the way to remember this is by the mnemonic:
Billy Brown Rapes Only Young Girls But Virgins Go Without.
An easy bonus point if you can identify from where the middle sequence of colours comes.
Ah, the benefits of a classical education!
Another useful mnemonic is a way of remembering which animals must be reported to the police if you twat them with a vehicle on the road. SHAMPOG-D which refers to Sheep Horse Ass Mule Pig Ox Goat Dog. Every day is a school day right enough!