IQ Tests - Stanford-Binet IQ Test
The test is completely free to take. You can take it for fun or for practicing math, verbal reasoning, numerical reasoning, and other question types commonly found on IQ tests. Answers to the questions can be viewed at the end of the tests.
There are many different types of IQ tests - The Stanford-Binet IQ Test website focuses specifically on questions from the Stanford-Binet IQ Test.