I'm writing to inform you that you have less than two years.
If I'm flicking through the latest issue of a technology magazine or tech Web site in 2015 and don't see a hoverboard, I'll be mighty disappointed.
And it won't just be me. Thousands, perhaps millions, of others, all waiting patiently for hoverboards. And you only have three years.
While you're at it, you wouldn't mind rustling up some flying cars, would you?
Actually, scratch that. People have enough trouble on tarmac, so God forbid you give them an extra dimension in which to travel. Can you imagine? There'd not be a house in the land without a 17-year-old's flying Vauxhall Corsa embedded in the roof.
No, I've got a better idea.
How about an electric car that we'd actually want to buy, with our own money?
Look, I know there are electric cars around at the moment, and really they aren't that bad. No, seriously, they're actually pretty good. As a means of getting from A to B they're only really as flawed as the distance between the two hypothetical points. If "B" is work and it's 20 miles away, then even the most geographically challenged of modern EVs will complete that distance in all weathers with consummate ease.
And they're pleasant to drive, too. Not exciting, necessarily, but pleasant. The kind of pleasant that's important when you've been arguing with the boss all day to find it's dark and raining outside, and there's a snake of eye-piercing brake lights stands between yourself and a fridge full of beer at home.
They're also cheap to run. You'll spend a pretty penny to put one on the drive, but after that a few quid per hundred miles doesn't sound too bad. But you knew that anyway, Science. We've been using batteries for years. Who really thinks about how much their iPhone costs to charge, even though the bloody thing seems to need charging every 8 hours? Just as well the thing doesn't run on petrol, really.
Sure, they have foibles. Not everywhere has a place to charge; 100 miles is a bit limiting for some people, and they really do cost a few bob right now. But you're clever chaps, you'll figure it out.
No, you just need to invent an electric car we actually want. A Nissan Leaf or Renault Fluence is OK, I guess, but who gets excited about putting a new Nissan hatchback or Renault saloon on the drive? Nobody was falling over themselves 20 years ago to buy a Nissan Sunny.
They were giving their right arms for a 200SX, though. Or a Mazda MX-5. Or the latest Golf GTI. What did all these cars have in common? They looked good on the driveway. They were aspirational. We may not need them, but we want them.
Still, don't rush yourself, Science. We expect you're rather busy with that hoverboard right now.