Watch engineers build a Mars rover!
Some comparison: The old Sojourner rover from 1997 was the size of a largeish R/C car. The Mars Exploration Rovers from 2004 that are still running (!) are the size of golf carts. This thing's the size of a Mini Cooper, and has a proportionally larger load of sciencey stuff packed on.
Instructables doesn't allow you to embed Ustream into Forum topics, so you'll have to go to Ustream to watch: http://www.ustream.tv/nasajpl
Via Bad Astronomy Blog, image from MSL website