Well, that was a straight-to-DVD series, but I’ll forgive you for mentioning Arrested Development.
Also from AD: “Why We Were Afraid of the 70s”.
Damn you, that’s exactly what I was going to pick!
If we can include AD straight to video, don’t forget
“Boyfights”
“Boyfights 2”
“Boyfights Cookout”
“Backseat Boyfights: The Trip To Uncle Jack’s”
Total Carnage! I LOVE IT!
Speaking of which – Smash TV!
Would the Office count, as it’s a spoof documentary?
Also there was “Secret Agent Clank”
Androids.
“Because androids have feelings toooooooooo”
-Joe
I almost never get to be the first to list something. I shall now bask in the glory that is ‘I posted it firstness’ basks 
“Girls Gone Wild meets Boys Gone Wild”
“CSI-The Morgue”
“Interviews With boring people”
“A Day In The Life of a Janitor”
“Rating The Automobile Waxes: Jwax vs. Turtlewax”
“Curling: The Spring Training Show”
“Canadian Cooking: How To Make Grilled Cheese Sandwiches”
I think this is the only reason I ever watched “The Fat Albert Show” They should take all those clips and put them on a DVD by itself.
Wormhole Xtreme (or was that a movie?)
That was Real Families - see Post #15. Real People was a real TV show.
IIRC, Intolerable Cruelty ends with Cedric the Entertainer hosting a show called Nail Your Ass. (The girls from Sex & the City were right: there is a lot more activity involving the ass these days.)
Speaking of S&tC asses, Sarah Jessica Parker’s character in Mars Attacks! hosts a cringe-inducing interview show, but I don’t recall if the show was ever named in the movie.
In a related vein, you have The Gray Ghost from Batman: The Animated Series, starring Simon Trent and voiced by… Adam West.
Well, the network never picked it up, but Jerry! had potential…
Hit the Buzzer, Win a Cookie, a fictional gameshow from the animated Garfield and Friends.
Also,
Hey Jorge!
Mrs. Falbo’s Tiny Town
and from the New Year’s Day 1984 episode:
DOUBLETHINK - where contestants use doublethink to vie for
valuable prizes such as razor blades and shoestrings (Sample Q&A:
Today, the chocolate ration is 3 grams. Tomorrow, it is 2.5 grams.
Has Big Brother increased or decreased the chocolate ration?
Of course, the answer is -He increased it.)
COMRADE LaLAINE EXERCIZE SHOW - Cmrd LaL orders viewers to do exercizes via the telescreen.
And finally - THE PBB CLUB - PBB standing for “Praise Big Brother!”
There was one on the animated version of The Tick. It was originally mentioned as a movie, but later treated as a TV show: The Mummy Speaks.
(The running gag was that you would never actually get to hear the mummy speak.)
Another from Married…with Children:
“Peas In a Pod” - Kelly tries out to play the daughter for the initially generic family sitcom. But when she makes comments to the producers about her own background, it gets changed into a raunchy, bawdy slapstick comedy (with remarkable similarities to the Bundy family & to Marcy & Jeff) that becomes a huge hit, only to get cancelled when an uptight housewife launches a campaign to end it.
Nitpick: I believe it was called Nookie in New York.
Other fictional shows from The Simpsons that haven’t been mentioned:
Admiral Baby
Police Cops
Ethnic Mismatch Comedy #644
Touch the Stove!
Gabbo
Herschel Krustofsky’s Clown-Related Entertainment Show
…and probably a dozen more than I can’t think of off the top of my head. I bet FOX could fill their entire lineup and then some if they made real shows out of every fictional show that’s ever been mentioned on The Simpsons.