ER: Started jumping when a lot of episodes revolved around Abby's family. Then Mark getting a brain tumor. Finally, the helicopter falling on poor Dr. Romano was the final nail in the coffin.
The X-Files: When Mulder left the show and only appeared in a recurring manor, in seasons 8 and 9. Season 9 had a lot of jump the shark moments as well.
Married...With Children: When they brought on Ted McGinely as Jefferson D'Arcy and some little kid who was supposed to be a cousin of the Bundy's. They also had a 'this season was a dream' thing going on when Peg and Marcy got pregnant.
Frasier: When Niles and Daphne got together
Friends: The 3rd or 4th time Ross and Rachel got together, broke up, got together, broke up, etc.
Will and Grace: When a week didn't go by without some famous guest star, somewhere around the fourth or fifth season.
The Cosby Show: When all the kids grew up and the brought on Olivia to replace them.
" You always take shots from folks who just don't get the joke!"
Joker- Mad Love