HackMaster (4th Edition)
Garweeze Wurld Kingdoms of Kalamar
Fantasy Fantasy (High Fantasy) Mythology / Folklore Mythology / Folklore (Fairy Tales) Fantasy (Sword & Sorcery) Science Fiction Weird / Surreal Fantasy (Arabian Nights)
Class Based (Pilot, Wizard, Scientist, etc) Dice (Various) Random Attribute Generation (during Character Creation)
Not for wusses, this is the system prized by The Knights of the Dinner Table. The Hackmaster GM Shield alone is worth the price of admission.
Hackmaster is based on the original Dungeons and Dragons game by E. Gary Gygax and Dave Arneson. Despite the name indicating this is the 4th Edition, this is the first release of the product (the edition is itself a bit of a joke).