My DHs rear derailleur cable broke, so he bought the necessary parts and started by putting his bike on the bike stand in the garage. I came hurrying out and said, "Don't do anything until I get over there. I want to help!". So I mostly watched, asked relevant questions, and helped thread the wire cable through the "housing" (not sure what it's called-the black tubular plastic portions that the cable goes through). The interesting part was calibrating it and adjusting the two screws on the rear derailleur to adjust the "limits". I proudly asked him if he knew how to do this because of the Parks Big Blue Book (bike repair book) that I bought him for Christmas. He replied, "No, I looked it up online". Oh well.

Now I think I could do my own.