You all recognize the music. Unfortunately, I have no musical background, so the best I can do is describe it.
Three. . . descending (?) notes.
Same three notes, one octave(?) down.
Same three notes, one more lower.
Same three notes, one more lower.
Something like:
DOO-da-da DOO-da-da DOO-da-da DOO-da-da
Repeat those bar(?) at least one more time.
Then, something like
DOO-da-da DOO-DOO-DOO
Good luck with that. (But it is a serious question.)
DOO-da-da DOO-DOO-DOO
There are a number of different ways to look up a piece of music on Musipedia, including whistling it into your computer’s microphone.
Please let us know if you figure it out!
The closest thing I could think of is the opening to Grieg’s Piano Concerto, but that doesn’t really fit your description.
First of all . . . what makes you think it’s a waltz? Does it have a rhythm that is, generally, OOM-pah-pah, OOM-pah-pah?
Can you tell us where you heard it? Is is played by an orchestra?
Definitely nothing from Carmen. "I ask to be, or not to be. . . "
Good point. Maybe it ain’t. Whatever it is, though, you’ll immediately recognize it.
More background: The recent “magneto man” thread in GQ reminded me of this. In the same doc in which he appeared (I think it might have been called “Superhuman” or something like that, there was another person who was (autistic?) (mildly retarded?). Whatever her case, her gift was that she had perfect pitch, and had an incredible learning ability to play musical instruments, just by playing around with them. It showed her playing [this unknown tune] on an accordion. The voiceover by her mother said something like, "What person could just pick up an accordion, and start playing [??? waltz]. I assumed that that was what she was playing, but that’s not necessarily the case. I actually though her mother said “Anniversary Waltz,” but I listened to that, and that is definitely not it. The tune her mother mentioned was by one of the classical composers, but, again, there might be some incongruity between the voiceover and what was actually being played.
If it’s not divined here, I will post it when I find the answer.
Hmmm. . . . this might actually be church music.
Do you remember if the three notes are major (“happy” sounding) or minor (“sad”)? If you sing the three notes, do they remind you of “Three Blind Mice” or some other tune?
There’s a part of Gershwin’s Rhapsody in Blue that sorta sounds like this, but I doubt that’s it.
BTW, was the woman accordion player Gloria Lenhoff?
Personally, I’d say they’re rather happy sounding.
And, yes, it is Gloria Lenhoff.
Heh. I’m glad you found it.
Gotta say, Pachabel’s Canon doesn’t resemble the descending three notes that shift octaves you describe. Those three notes, which are ascending arpeggios, then shift a single note downwards and repeat. And I dunno what would describe the final “DOO da da DOO DOO DOO” part you mention at the end.
Basically we had no shot in hell of figuring this one out. 
Hmm. Okay, that isn’t even close to a waltz. Oh well.
You may find the Pachelbel Rant worth listening to.
And I think I’ve proven this decisively.:o
Damn, that’s like the last thing I’d guess (right after the 1812 Overture, based on your description.
Yeah, put me down as another “I never would have guessed that it a million years.”
So, I had to google the phrase “Pachelbel Waltz.” And apparently something called “Pachelbel’s Waltz” shows up on this Folk Music Index. I wonder what it sounds like.
FWIW, old thread: Popular songs that are waltzes
It’s possible that the piece in the movie was a waltz version of Pachelbel’s Canon. It’s quite easy to transform that melody into 3/4 time. That said, the rest of the description wouldn’t have helped us out.
I might have been misinformed. I’ll keep you posted.
In addition to having no musical background, I’m also pretty bad at trying to reproduce a coherent melody.