According to wikipedia, the Doctor took the Tardis from a museum.
The Doctor's TARDIS was for most of the series' history said to have been stolen from the Time Lords' home planet, Gallifrey, where it was old, decommissioned and derelict (and, in fact, in a museum). However, during the events of "The Doctor's Wife" (2011), the ship's consciousness briefly inhabits a human body named Idris, and she reveals that far from being stolen, she left of her own free will.
(I vaguely remember hearing/reading this elsewhere although I am not sure it was ever mentioned in the new series.)
Why was the Tardis in a museum to begin with? Presumably, that would mean it was something special. Either used by a dignitary, first of its kind, or perhaps a Gallifreynian video performance of Space Oddity was filmed in it.
Has it ever been discussed?