Even though they can't actually levitate, "hoverboard" self-balancing scooters have become a huge hit. Celebrities are jumping on the two-wheeled bandwagon, either signing deals to promote the next big brand or attaching their name to one of their own. That's helped boost sales of the popular toy in the UK, but the law actually dictates that they can't be ridden in a public space.

The Crown Prosecution Service says that the Highway Act 1835 limits hoverboard use on pavements, while various vehicle registration agencies won't licence or register them for road use. Riders can be fined up to £500 if caught doing so, but London Mayor Boris Johnson is making it his mission to legalise their use based on "intergenerational fairness."