Arcade machine play screens of Gorf can be seen in these movies - 1982's Fast Times at Ridgemont High, and 1983's Joysticks. An arcade cabinet can also be seen in 2006's The Benchwarmers.
Gorf is an acronym for 'Galactic Orbital Robot Force'.
The programmer called it Gorf since it's Frog spelled backwards. (I don't know why either.)