The sword that Ronnie Jean pulled from the stone is the master sword from the "Legend of Zelda" video game series.
There is a slightly confusing continuity error in this episode. It is when Jerry upsets Black Steve and is forced to watch The Color Purple. The problem here is that the movie was released in 1985, which is 3 years after this episode. To make matters worse, in the season one episode E.T., Todd gives Steven Spielberg the idea for the movie. This means that Steven got the idea sometime after the eleventh of June, which was when E.T. was in theaters, made the film, released it to theaters, and released it on video in about 3 months, which is when Michael Jackson released Thriller. Plus, in The Woz episode, Dave mentions that he was Michel Jackson and he would release Thriller, meaning that Thriller should have released before the events of The Woz happened, meaning that Thriller released before Mr. Larity owned the company.