GURPS
GURPS is a roleplaying game made by Steve Jackson Games. It has lots of numbers and expansion books. It is so flexible that you can bend it in half and fold it inside itself. It is the paradigm of the Simulationist category of games. All simulationist games since GURPS secretly aspire to kill GURPS and wear its skin while drinking the delicious delicious heart's blood.
The storyline created by the 300,000 gurps books are very stupid, and akin to a sci-fi novel written by a 12 year old with downs.