Train stations in the UK sometimes broadcast mosquito noises that are so high-pitched they can only be heard by those under 25 years of age, but Japan's taken it one step too far with this age prediction gadget.
Designed to be used on blind dates to determine their age, the Age Prediction Machine plays a buzzing mosquito sound, which will tell the user whether they're actually a teenager, in their early 20s, 30s or - heaven forbid! - over 40, depending on how well they can hear it. If they start slapping imaginary mosquitoes away on the 40-year-old setting (which should be the loudest), then you know you've been set up with a goose of a blind date. [Plusd itmedia via Newlaunches]