The crazy, wild and sometimes wacky game system of David Hargrave. Specifically, the individual, digest sized booklets published by David Hargrave that covered the initial system of Arduin and its statistics. For its time it was truly revolutionary, pushing at the boundaries of the "accepted" unbreakable rules. The idea of going beyond 10, 12 or even 20th level was an extreme thing in the beginning, and DH poked holes in it by showing scales of 30, 50 and even 100 (!) levels of character progression. He also brokered a lot of common sense and danger into games, scrapping away the fluff to say that adventuring is dangerous and deadly: act stupid, mess up, or forget to plan and you can get yourself and your buddy killed.