Inspired by this T-shirt design, by Jason Casteel:
Ellindsey designed a TARDIS Transformer toy that goes from this:
But wait. It gets better. Go to MakerBot Thingiverse, and you can download the instructions for 3D-printing out the pieces and making one for yourself.
Truly, we live in wondrous times. If you have access to a 3D printer, anyway.
Via Topless Robot.
Thanks to Sean and Patrick for the heads-up.
(If you stumble across a cool Doctor Who thing, feel free to email me with a link.)