I first saw this on Top Gear, and assumed it was a load of rubbish, but today I tried it out and it actually works, if you walk away from the car continuously unlocking/locking it until it stops, and go a bit further away so that the car will not un/lock. Then out the car keys next to your head and point them directly at the car it will un/lock.
How does your head/brain/etc increase the range of the keys? And why does it only work next to your head if you point the keys directly at the car, when you do not have to point towards the car when in normal range?