Youtube is great for visual instruction.
A couple of oddball examples where Youtube was a help to me was:
1) Putting my tent together. Our neighbour gave us her old tent which had some weird connection system. We were able to assemble it so it stayed up, but it wasn't correct. I found a video where the people in the video demonstrated (without talking) how to put the tent together correct. All the sound of a porn movie soundtrack.
2) Removing the bearings from my rollerblade wheels. The wheels wear out much faster than the bearings, so you need to take the bearings out of the worn-out wheels and put them in the new wheels. I couldn't figure out how to do it, but it took about 5 seconds of a video to see how easily it was done.