Da Yoopers parody of Jingle Bells - “Rusty Chevrolet”: “I strike a match to see the dash, and then I start to pray.”
No love for Spike Jones?
Joan Osborne seemed to disappear as quickly as she appeared in the mid-90s, but I still occasionally find myself wondering “What if God Smoked Cannabis?”
I remember reading an interview with Billy Joel years ago where he mentioned that when he was writing the song “Honesty”, his placeholder lyric was “Sodomy”. So of course that’s what always pops into my head when I hear that song.
Another one from my childhood.
Glory, Glory, Halleluiah. Teacher hit me with a ruler.
I am you, in this regard.
I love Spike Jones, but in most cases, I have never heard the originals.
Is the “Dance of the Hours” segment of Fantasia considered a parody? The music itself was played completely straight, but I don’t think ballet-dancing hippos is quite what Ponchielli had in mind.
I never developed full lyrics, but every time I see a box of mac and cheese branded as “shells and white cheddar” I hear it to the tune of Knights in White Satin.
shells and white cheddar
never tasting so good
always a bummer
have something else, you should…
Well, if we’re tossing out non recorded types of parodies at college we used to sing to the tune of a certain BTO song.
Eatin’ lots o’ pizza,
Every day.
Eating lots o’ pizza
Every way.
Eating lots o’ pizza
Sure tastes great.
Eating lots o’ pizza,
And getting overweight.
Glen! Glen Glen Glen!
RIP Jimi Jamison, eh? What a voice!
And “Winter Wonderland?” Slightly NSFW:
Whenever “My Way” comes up, I have the Sid Vicious/Sex Pistols version in my ears. The lyrics are unchanged, but of course it’s a parody.
Some of the childhood parody lyrics reminded me of the alternative lyrics we learned, as kids, to “Strangers in the Night” (spoilered because they are slightly NSFW, and because it’s crass humor that a 10-year-old would find hilarious):
Strangers in the night
Exchanging rubbers
This one is too tight
I’ll try another
This one is too loose
But it will hold the juice!
My cousin and I used to sing this at the top of our lungs in the back seat of the car; we were both young enough that we didn’t really know exactly what the lyrics meant. 
Not that I often hear “Strangers in the Night,” but when I do, those sophomoric lyrics come right back to me.
In the version I remember, the last line was “It would fit a moose!”
Mine eyes have seen the glory of the burning of the school. We have crucified the prinicipal and broken all the rules. Something something something.
Glory glory Hallelujah. Teacher hit me with a ruler. I bopped her on the bean with a rotten tangerine. The truth goes marching on.
My version for a 10-year old was:
Changes in the night
With seven children there’ll be
Changes in the night…
I almost choked on my salami sandwich just now! 
My ten-year-old sense of humor is still intact! 
I can’t hear the up-tempo finale of the “Dance of the Hours” (after the “Hello Muddah, Hello Fadduh” section) without inserting the lyrics from “The Garfield Opera”:
Eat!
Have a bowl of shredded wheat!
Add some sugar, make it sweet
It’s so neat
When you mix it with some fruit or berries…
I wanted to post Bart Simpson’s version of this, but couldn’t find a clip in English. 
“What’s Up” - that’s a great self-parody song by Four Non-Blondes.
or, wait
I can’t hear the opening lines of I Am The Walrus
“I am he as you are he as you are me
and we are all together”
without thinking of The Rutles homage
“I know you know what you know but
you should know by now that you’re not me”