This is pretty cool.  This webpage shows a scaled version of our solar system, where 1 pixel equals about 1000 kilometers.  You start off at the sun, and you scroll to the right until you hit Mercury.  Then Venus.  Then Earth, and so on.  Not only are the distances between the planets to scale, but the planet sizes are to scale.

Be prepared for A LOT of scrolling.  This is a looooong webpage.