The phrase "jumped the shark" is used to talk about tv shows that have gone past the point of interest and it refers to the episode of Happy Days when Fonzie jumped the shark. At that moment, Happy Days was a shell of it's former self, lost in ridiculous, gimicky plots.
Having said that, I think House is about to jump my personal shark. I tried to watch it last night, but found that for the most part, I just don't care. House is cranky, Wilson continues to pacify him, Cuddy sighs a lot, patients get cured in the last five minutes thanks to some amazing revelation. It's just a little boring and predictable.
I stopped watching Grey's Anatomy about the time Katherine Heigl's character was having visions of her dead fiance. I stopped watching Heroes around the end of season two when you couldn't tell who was good, who was bad, or what year you were in. Ugly Betty lost me when the writers seemed to be pulling plotlines from bad '80's soap operas.
Book series are like that for me too. After a certain point, some series just lose me. I've stopped reading at least three that just got so bloated and convoluted, I couldn't keep from rolling my eyes.
How about you? How long do you stick with a book or tv series? Any shows you've given up on recently?