Monkey testing is the art of generating random tests via automation. There are smart monkeys and dumb monkeys. Dumb monkeys randomly exercise functionality in an application -- for instance, randomly clicking UI elements or randomly inserting data, rarely with validating output.
They're often used to expose issues like memory leaks. Smart monkeys, on the other hand are, well, smarter! They randomly interact with the software being tested, but have state or model information which allows them to validate the results of interaction. Some smart monkeys are so smart that they actually queue up new tests based on the results of previous tests.
