Cartoon Action Hour is a role-playing game (RPG) designed to emulate classic action-adventure cartoons, such as ThunderCats, He-Man, Transformers, G.I. Joe, Visionaries, Inhumanoids, Centurions, Thundarr the Barbarian, M.A.S.K., and Bravestarr.
It was e-published by Spectrum Games as a PDF role-playing game in early 2002, where it garnered a sizable cult following. This prompted Z-Man Games to offer to publish the game as a hardcopy edition. The material from the PDF was revised and expanded upon for the 2003 print version.
Source: Wikipedia, "Cartoon Action Hour", available under the CC-BY-SA License.