A couple of weeks ago I put some of this back into practice when I visited Meon Junior School in Portsmouth (UK), and talked with two groups of 35 Year 5 students (10 year olds). They had recently been learning about the Sun and the Moon, so I decided to talk about the solar system as a way of introducing the idea of the scale of the universe.
I developed a solar system model for this visit. This was inspired by the model described here. And made heavy use of this Solar System Scale Model Calculator.
Here's the version I coloured in and cut out to use to demonstrate in the class. Just to be clear this is an accurate scale model - you can fit the Sun and all the planets on a single sheet of A4 then, cut them out and space them over a bit more than half a mile for the proper orbits. We could only fit the Sun, Mercury, Venus and (with some squeezing) the Earth in the classroom. I think that really impressed the kids.