Matt Smith wants you to make your own TARDIS birdfeeder:
It’s easy! Just go pour all the milk out of that half-gallon carton in the fridge and get started. Full instructions can be found at the CBBC’s official site for Blue Peter.
Someone called aheavens made one, and posted a picture of it to flickr:
(If you stumble across a cool Doctor Who thing, feel free to email me with a link.)