Future Me is a simple online alternative to a time machine, allowing you to send a message to be emailed back to yourself at some pre-defined point in the future.

Follow the lead of three hundred other users and send yourself a post-dated check-up: "Dear future me, did you grow up to be a fireman, do you still have the use all your limbs, how big is your bald patch, is Celebrity Love Island still on TV, and if so why?"

And, if you're the kind of person who takes offense when no-one remembers your birthday, fear not, you can always rely on future you.

(Image used from Fritz Lang's 1927 film Metropolis)