John Ritter's death
On September 11, 2003, John Ritter suffered an aortic dissection which ended his life. Contary to rumor and tabloid reporting, Ritter did not "drop dead on the set" of "8 Simple Rules." After experiencing discomfort during rehearsal that afternoon, crew members took Ritter to a nearby hospital where he died that night. Fittingly, John Ritter's final interview took place on the set that day with the Museum Of Television & Radio. Following Ritter's death, ABC announced that the show would continue after a hiatus, and would incorporate the death of Ritter's character. The three new episodes that Ritter completed were aired with reflections from the cast.
The show returned on November 4, 2003 with a one hour episode, "Goodbye", dedicated to Paul Hennessy's death. Subsequent episodes dealt with the family's reaction to his death and their moving on. The first four post-Ritter episodes were shot without a live audience, in a respectful transition from the shock of his passing. Suzanne Pleshette and James Garner guest starred as Cate's parents. David Spade later guest starred as Cate's wayward nephew, CJ. Both Garner and Spade eventually received starring roles.
(sourced from Wikipedia)