A caveman, along with his friend of considerably more intelligence, once inadvertently piloted the Doctor's TARDIS to the 20th century.
Observing the First Doctor leaving the craft, they both entered to investigate its presence which resulted in the other caveman flicking a switch on the console and catapulting them into Earth's future. Upon their arrival, they were mistaken for the ZZ Top who were scheduled to perform in a nearby concert hall. After being cornered by a mob of fans who took their clubs and clothing, they returned to the Stone Age whereupon they were arrested by a policeman for stealing the TARDIS and appearing naked in a kid's comic. (NOTVALID: Bloody Ages Ago)