Actually Okra Cola was from The New Show, but I’m just picky.
From the Simpsons’ freezer:
Much Ado About Stuffing
Tubbb!
from Ghostbusters:** Sta-Puft Marshmallows**
from Pulp Fiction: Big Kahuna Burgers
Haggis actually exists in Scotland. They have the Ceremony of the Haggis, complete with singing, dancing and bagpipes. You’re right, it is a horror story to freak out the tourists, and they imply that it’s something like ground up sheep guts. It’s actually lamb ground with oatmeal, onions, and spices. I’ve had some, and it’s not bad. It tastes like taco meat.
Larry Niven invented a number of fictional food and drink items (plus some non-food intoxicants like sparkers in one or other of his short stories about an alien bar) - Louis Wu can often be found tucking into some local delicacy.
On the Turkish Delight thing; some people don’t like it because it is too sweet. I’ve seen it made without the gelatin at all - just rosewater, lemon, sugar and cornflour (in fact I think this may be the traditional recipe, although I’m not sure what would have been used before cornflour came on the scene).
The best way to enjoy the stuff is alongside a cup of Turkish coffee - this stuff is served in tiny little cups like espresso, but is very much stronger (it isn’t filtered at all - you just stop drinking when the cup is about a quarter full) - the overpowering sweetness and fragrance of the Turkish delight sets off the intense aroma and bitterness of the coffee just perfectly.
Yes!! I always fantasized about that fruity wallpaper, and that chocolate river, and the little land of candy. Mmm, Everlasting Gobstoppers and that gum that tastes like a whole meal!! I want to go to the Wonka Factory!!!
The chocolate river is (in my opinion) the weakest element in the movie (I realise you may have been talking about the book) - it just looks like dirty water - maybe someone should digitally remaster it - I’m sure that could be done with today’s technology.
Heh, I thought it looked like it might taste like Chocola. I love Chocola!!
In Journey to the West, Son Wukon, while slacking on the job as some minor official of the Celestial Court (he’d been given the job as appeasement), crashes a party and promptly eats all of the Celestial Peaches, drinks all the Celestial Wine, and prescibes himself the entire stash of the Celestial Pills.
(Well, okay, I fudged a bit on the translation, but you get the idea. :D)
Pratchett’s beer is Turbot’s Really Odd, which plays off the “old peculiar” theme. There’s also a beer from XXXX called Funnelweb, I believe.
Yeah, Old Peculier is pretty good, but I like Bishop’s Finger better! 
While Scots eat more lamb and mutton than we do in the US (fond memories of 20 years ago eating ground mutton pies topped with baked beans), haggis is NOT made of ground lamb.
2 lb. dry oatmeal
1 lb. chopped mutton suet
1 lb. lamb or venison liver, boiled and minced
sheep heart, boiled and minced
plus spices and onions, all stuffed into a lamb’s stomach to cook.
You may have been told it was just lamb to get you to eat it. And really, liver and heart minced up is perfectly edible and many people actually like it.
Now for fictional food, nothing can beat the cans of “Food” from Repo Man. Best consumed with cans of “Drink”.
I’ll submit Pervish food from Robert Asprin’s Myth Adventures series–no specific dishes are ever named or shown, but we can draw certain conclusions from the context.
Aahz: “I tell you, kid, the main problem with Pervish food is keeping the goo from crawling out of the bowl while you’re trying to eat it.”
Then there’s the fact that the Bazaar at Deva had an ordinance requiring any place serving the stuff to move constantly from place to place to keep the smell from causing the collapse of the local economy. When Skeeve got lost he tried to track the place by smell, and wound up finding a big pile of dragon(?) dung instead.
Also, here’s some more on spoo from the Babylon 5 Encyclopedia–possibly the most amusing description of a food source I’ve ever read, notably the comment:
“Spoo are the only creatures of which the Interstellar Animal Rights Protection League says, simply, 'Kill ‘em.’”
Another one from the Simpsons: Tomacco, the tomato / tobacco hybrid
Razzleberry dressing from “Mr. Magoo’s Christmas Carol.”
Saurian brandy from “Star Trek.”
Manna from you-know-where.
Another one from The Simpsons, Wadded Beef.
And from Futurama; Admiral Crunch and Archduke Chocula.
Ukulele Ike, I’m pretty sure that Tree Frog Beer was a real beer back in the seventies. That’s probably where the comic got it from.
I believe the plural of schmoo is “schmoon.”
Who can forget lovely Aunt Beru’s blue milk from Star Wars?
You can actually make it if you’re a chef in Star Wars Galaxies.
Oooh! I got one!
Blue string pudding.
Personally, I’d like to try a good old-fashioned porcuswine burger like they make at McSwiney’s.
Don’t forget New Shimmer. It’s a floor wax and a dessert topping!
In2001: A Space Odessy (Arthur C. Clarke’s book, not Kubrick’s movie), when the astronaut first arrives on the alien world, he is fed a mysterious blue substance which has a completely neutral flavor, and sort of takes on whatever flavor you happen to be thinking about at the moment.
In several different incarnations of Star Trek, a Regular Cast Member offers the Guest Star a bottle of a mysterious beverage.
Guest: “What is it?”
Regular: “It’s green!”
In the Disney movie of 20,000 Leagues Under the Sea, Captain Nemo offers his guests some oddities. I can’t remember most of them, but “flesh of unborn octopus” seems to stick in my memory.