Because my Harry Potter mad friends think it's like the flying ford anglia that the Weasleys had and it apparently has an invisibility button! The car was Rupert Grint's favourite prop from Harry Potter hence the car is called Rupert!
My cars have all had unofficial names.
My first car (fiat punto) was called thug, because the last 3 letters on the number plate where thg.
My micra was called gladys, because it is a bit of an old grandmas car, and i liked the name gladys for some reason.
My new car hasnt got a name yet, as ive only had it a week.