Founded in 1967 by Simmons and fellow Diner's Club refugee Len Mogel, Twenty First Century was created to publish a "counterculture" magazine called Cheetah. While Cheetah failed, the partners had more success in the 1970s with Weight Watchers and National Lampoon magazines. Under Simmons' direction, National Lampoon's entire editorial staff was fired and replaced with his children (Michael Simmons and Andy Simmons), as well as Peter Kleinman and Larry Sloman. The magazine expanded into radio, theater, records and film.