Trying to balance objects is always fun to attempt. One of the easiest things to balance would be a long stick. I really shouldn't need to mention this, but the stick can't weigh too much.
To make it even easier, add any kind of weight to the top end of the stick. The heavier the weight is, the easier it'll be to balance the stick. If you were to reposition the weight, you'll realize that the stick will "move" more the lower the weight is positioned.
This is a pretty basic physics experiment anyone can try at home.