What's a TARDIS?
That is what Doctor Who uses to travel through time and space. It stands for Time and Relative Dimensions In Space (I think; it has been a while since I have watched Doctor Who). A TARDIS can take any form, but Doctor Who's is stuck in the form of an old British policeman's call box. It's bigger on the inside than on the outside.
Doctor Who is a British television show that started in the 60s and has been running off and on even to the present day. It's a fun show.