Banging your head against a wall uses 150 calories an hour. See more

Those stars and colours you see when you rub your eyes are called phosphenes. See more

The right lung is slightly larger than the left. See more

There are 100 million internet users in China. Some of the sites they can't access are BBC news, Amnesty International and Dalailama.com. See more

The 'save' icon on Microsoft Word shows a floppy disk, with the shutter on backwards. See more

A single individual, Dr. Lieven P. Van Neste, owns over 200,000 domain names! See more

The heart beats about 100,000 times each day. See more

The electric chair was invented by a dentist. See more

You use over 70 muscles to say one word. See more