These are all examples of wire splices that were hidden in the walls, a big no no. Not only is this a fire hazard, it makes troubleshooting essentially impossible if you ever have trouble with the wiring in the house.
This was actually in the basement, but I found it so amusing I had to put it up here. This box is original to the house and when installed probably had a ceiling light fixture attached. At some point the previous owner took off the old light fixture, connected several different circuits to the box and then wired them all together in some interesting ways. I think this box probably wins the prize on illegal electrical work, the wire splices were illegal, there was too much wiring in the box and the box was hidden above a drywall ceiling.
Here are some more pictures from the basement, the picture on the left is the original distribution point for telephone service. The picture on the right is our current phone distribution point (the new one also handles the TV signal and the computer network).