Who hasn't wanted their own TARDIS at some point? The Old Girl (or Sexy, as she prefers to be known) can be yours in miniaturized form, complete with light on top.
This micro-TARDIS just looks small from the outside (5cm tall) - there's a lot more going on inside.
To get the best colo(u)r, I recommend printing with blue ABS, and covering it fairly evenly BEFORE printing, with a blue Sharpie. This changes the print colo(u)r from blue to dark blue. (Approx 0073CF to 0000B8)
---Bits and Pieces---
You will need 1x 5mm LED (in white, blue or UV), some wire, 2x small cell batteries, and an empty drinks can (or similar).
I've got some smaller LEDs coming in the mail, and I intend to get this small enough to attach to one of my infamous hair clips. The photograph shows my iterations, but it looks a bit like the TARDIS is moving through time in a way that only Baker-era special effects could claim ;)