A professor showed this to me in a ceramics studio. We set it up on a potter's wheel as a demo to learn how to center a piece and it was a fun day indeed. I later showed this to my 3 year old cousin and she flipped out.
What you will need:
1. An old record. (One that you don't mind scratching.)
2. An empty cottage cheese / yogurt container
3. One sewing pin
4. A way to spin the record. I am just using a pencil and spinning it with one hand while holding it in place with the other. This way takes two people but a "lazy susan", hand drill set up, or bearings make it easier.
Step 1: Make the Speaker
Make sure that the container is clean and then poke the pin through the center.