There was a cartoon tv series in the late 80s (derived from a children's story book series) called "Inspector gadget", about a detective who could make mechanical things appear from his body, such as a portable helicopter, or extendable arms, or a toaster and lots of other things. He would say "Go Go Gadget (insert word here)" to make his various mechanical items activate.
This guy on msn has made the logical conceptual leap of imagining an extendable "gadget" penis, as did so many schoolchildren at at the time.