Robert Full and a team at UC Berkeley studied Agama lizards to see how they utilized their tails for balance when they run and jump. It seems that the reptiles needed to tilt their bodies upward to land properly. They applied this principal to their Tailbot, a wheeled lizard. The idea here is to create a robot that can jump over gaps and land safely and the team figured that the motion involved went as far back as dinosaurs. The results of their study can be found in the January 2012 edition of Nature.
Watch the video and note the subliminal glee that Full gets when he realizes that the velociraptor in the film Jurrasic Park has that same balance of body and tail.