Dang, why is this so popular? This is my answer, too. And that was for an 11th grade english class 12 years ago!
There is nothing useless about Chaucer… 
Noooo!!! That code wasn’t for Super Mario Bros!
The Konami Code:
Up Up Down Down Left Right Left Right B A (select) Start
Most remember it as the thirty lives code in Contra.
Oh, and:
Ha-do-ken: Down, down-forward, forward, punch
Shoryuken: Forward, down, down-forward, punch
Ah, another one:
high punch, low punch, high punch, low punch, low kick, low kick, back+high kick (Kung Lao combo for Mortal Kombat 3).
Twoallbeefpattiesspecialsaucelettucecheesepicklesoniononasesameseedbun.
OLive 1-5407 (the phone number in the house from which we moved in 1966).
On the other hand, I can still recite all of Jabberwocky and the complete Yarn of the Nancy Bell with inflection and I do not consider either of those to be useless.
Doom 1 there … the first is God mode, IIRC, the second is all weapons, and the third is clipping … off?
And then there’s the code for … Mortal Kombat? up down left right A right down gets you into this funky mode that makes it really easy to get fatality victories.
I had the periodic table memorized at one point to disturbing degrees of depth, and the known genealogy of my father’s family several generations back (you want to know what Henry Mills Alden was doing in his 30s? When his kids were born? What day his christening was? Yes, I was and am a dork).
Odd, that’s exactly what I was going to post. And I haven’t seen that film in years.
I’m just going to be cynical here… just for a split-millisecond… and say my Marriage Vows… they certainly turned out TOTALLY Useless!
cynical attitude has now passed … Whhhooooooosssshhh! 
The Gettysburg Address.
The Cremation of Sam McGee
Bill the Bomber
My Masonic Ritual (for Maryland, Missouri, Panama and Germany, all so similar, all so different).
Every major-party presidential and vice-presidential candidate in American presidential elections since 1948. (I’m not American.)
The password to get to level 15 in Lemmings for the Mac is HMLICINMEP (haven’t played this game for about a decade). It’s a cool level, too. Furthermore, Mario used to be called Jump Man, and the M. Bison and Balrog characters from Street fighter used to have their names the other way around (they changed it because M. Bison on a boxer sounded too much like Mike Tyson).
I also know the that All Your Base came from a Genesis game called Zero Wing, by Toaplan. And all the words from that intro. 
~ Isaac
nameing the connections from Napolean’s army to Apollo 11.
The helping verbs (like ccwaterback except in a different order): is am are was were have has had do does did might may can would could should will shall must be being been
Edgar Allan Poe’s The Raven.
etaoin shrdlu (letters most used in the English language, from the comic strip Pogo, and I believe it was a Straight Dope column as well)
The lyrics to way too many 80’s alternative songs.
The free first 6 levels of Doom. I played those so much they’re burned into my brain.
The opening of the 50s Superman TV show with George Reeves, keeping very close to the original tone, emphasis, and rhythm.
While reading about old letter prefixes for phone numbers, I recalled the phone number for the apartment my family lived in before we got a house when I was about 9. Geek points: I realized the last 4 digits, 8191, is 2¹³-1. That means I haven’t thought about the number at least since I became a programmer, over 30 years ago, or else I probably would have remembered making the connection.
I spelled a word wrong that no one would ever ask me to spell.
I’m SO upset!
I think our educational system failed to make me sufficiently compulsive.
That word is useless isn’t it.
iddqd
idkfa
idspispopd
As soon as I read the mention of Doom codes, I averted my eyes and tried to think of them. I couldn’t, but lo and behold, I was able to type them with hardly a typo.
I’ve played piano sporatically throughout my life, and I have very good muscle memory in my fingers (hence the codes). I can play songs that I haven’t touched in ages with fantastic accuracy, but only if I’m sufficiently distracted. If I think for just one moment about what’s coming up, I freeze.
My ctrl+esc p q (1, 2 or 3) sequence for loading quakes 1 two or 3 in windows is similarly burned into my brain.
Ah, yes - iddqd for degreelessness, idkfa for Keys, Firearms, and Armour (or just idfa for that without keys), idspispopd for no clipping in Doom 1 or idclip for Doom 2, idclevXX for level skip, idmusXX for music change, idbeholdX for powerup toggle… I can’t think of any others.
The real question, though, is this: Does anyone know why the letters ‘dqd’ appear in the god mode cheat?
~ Isaac
Do you mean “Friends, Romans, countrymen” or “O pardon me, thou bleeding piece of earth, that I am meek and gentle with these butchers.”?
Tunic button configuration for Foot Guards regiments:
- Eight equally spaced buttons for Grenadier Guards
- Four groups of two for Coldstream Guards
- Three groups of three for Scots Guards
- Two groups of four for Irish Guards
- Two groups of five for Welsh Guards
George’s ‘bergen’ soliliquy in Albee’s “Who’s Afraid of Virginia Woolf”
“When I was sixteen and going to prep school…”
“The Cremation of Sam McGee” by Robert Service
“The Congo” a helluva poem by someone whose name I’ve forgotten.
Fat black bucks in a wine barrel room
Barrel house kings with feet unstable
Sagged and reeled and pounded on the table
Pounded on the table
Beat an empty barrel with the handle of a broom
Hard as they were able
Boom boom boom
With a silk umbrella and the handle of a broom
Boomlay boomlay boomlay boom."
And it goes on