Fun interact-able websites:
A page built around an Adobe Flash where there is a man waiting on a desk. If you bring your cursor near his face, he will smack it away. This will actually move the cursor.
If the moon was only a pixel, this is what our solar system would look like. It is really far across horizontally, but is displayed like a giant chart. You can also change the unit of distance in the center near the bottom. Space really is just mostly made up of space.