Intelligence tests have been around about as long as humans have. But the term IQ, or Intelligence Quotient, is relatively recent, dating from 1912, when German psychologist William Stern first used it in reference to scoring methods for intelligence tests performed on children.
Lots of people seem to enjoy taking online intelligence tests, and there are plenty on offer. The list below includes many of these free online tests, as well as sites offering more serious intelligence testing resources.
Please feel free to add any relevant sites to this list, along with a summary for each.