When did a TV show/cartoon jump the shark?

[Woops]

"Fairly Oddparents" is one cartoon that had a decent premise (kid with magical fairies that deals with  a sadistic babysitter, an eccentric teacher/fairy hunter, and wishes that goes haywire), but badly executed with overly annoying characters and bad writing.

[Out of the Blue]

badly executed with overly annoying characters and bad writing.

That seems to be true for most movies and shows on TV right now.  I think it really boils down to a lack of talent in Hollywood and the entertainment industry as a whole.

[Out of the Blue]

I don't think "Gilligan's Island" ever jumped.

[Out of the Blue]

"Miami Vice" is my favorite TV show of all time and I think it went in the fourth season.  There was this episode that had James Brown in it and it was just horrible.  It was about UFOs and some government cover up.  The irony is that the best and worst episodes of the entire series were in the fourth season.

[Woops]

"Gumby"

The 1988 revival series since the 1950's and '60's shorts had their original score replaced with a synth background, which was featured on the newer episodes.

[Out of the Blue]

I don't think "M.A.S.H." ever jumped.