Josh Jackson wanted to enter his kids into the 3rd Annual Madison Soapbox Derby in Decatur, Georgia. And because he and his kids are Doctor Who fans, they decided to build a TARDIS-themed racer. No one else had attempted this before, as he explains at Paste:
Some quick online research found plenty of people who had built a replica Tardis, but no one who’d tried to make it roll down a hill with their child inside.
This is what he ended up with:
Click over to Paste for a couple more images (including the one of the Doctor-appropriate bumper stickers on the back of the racer) and some explanation of how Jackson built the thing.
(If you stumble across a cool Doctor Who thing, feel free to email me with a link.)