I have a vague memory of hearing about a jazz musician who composed music in ridiculously weird time signatures, just for the lulz. One of his more unusual bits had a time signature of 15/13 or something.
Any idea who this was.
You might be thinking of Dave Brubeck’s “Out of Time” album. I wouldn’t call the time signatures “exceptionally weird,” but they were somewhat unusual.
The first thing that came to mind is Bernstein’s* West Side Story*. I don’t have a good cite right now, but it’s got some really wacky signatures.
Aside from Brubeck (I agree with pulykamell about his stuff not being all that weird) you might be thinking of Don Ellis - Wikipedia
Crap. I mean “Time Out” album. Damn faulty cusp-of-middle-age memory. “Out of Time” is, of course, an R.E.M. album.
The song “America” is particularly cited for having alternating bars of 6/8 and 3/4. Here it is notated. You can notate it in one time signature if you wanted, though (and it’s not unusual to see it notated just in 6/8–and from my experience, it most usually is.)
Could be Brubeck’s Time Out, Time Further Out, Time In, Time Signatures, or one of his hundred-odd other albums.
<joke>
So, a band has just gotten some new sheet music, and it’s in 7/8 time. But none of the band members has ever played a piece in 7 before, and nobody really knows how to count it out. After several minutes of puzzling over it, the drummer exclaims “Wait, I’ve got it-- It’s ONE-two-three-four-Five-six-se-ven”.
</joke>
I’m hardly a music expert, but is there even such a thing as a 13th note?
You don’t mean “Chain Reaction” by Hank Levy (and Don Ellis), now do you?
Don Ellis never met an odd time signature he didn’t like. Very cool to hear and great to play, though. We’re still catching up to Don Ellis, like Mingus and Brubeck and Gil Evans.
I also recommend the Don Ellis documentary: http://www.amazon.com/Don-Ellis-Electric-Heart/dp/B00IKXQU8U
… or any Don Ellis album. 
The most distinctive “odd” tune of Brubeck’s was Unsquare Dance, which was in 7/4. He also wrote a tune called Eleven Four, which is very nice, and another called World’s Fair in 13/4.
Listen for Joe Morello’s response when they nail the ending.
No. (ETA: Or maybe I should say, yes, in theory there’s no reason such a note couldn’t exist.) But there are “irrational” time signatures out there. I’ve never seen 13, but I’ve seen 10 and 12 in the “denominator.” See Brian Ferneyhaugh. It’s not exactly mainstream notation, but it’s out there. 99.99% of the time, all you’re going to see as the bottom number is some multiple of 2.
I don’t know if this is interesting or not, but I’m a wedding photographer and do a lot of weddings in cultures outside the typical “American wedding.” I’ve noticed that in Greek and Indian weddings, in particular, it is not uncommon to hear music in 7s, and that people seem to have no problem dancing to it and counting it out.
Brubeck’s Take Five is a classic, and another one that jumps to mind is Pat Metheney’s The First Circle
Lots of music in unusual signatures is listed here.
That’s not really all that unusual; that pattern also shows up a bunch in Man of la Mancha as well, and is a fairly common Spanish dance rhythm.
Sure: it’s 1/13th of a whole note.
It’s a little silly, though. The thing is, at the end of the day, the bottom number of a time signature is largely irrelevant. A composer may choose to write something as 2/2 instead of 2/4 because they want a certain feel, but that’s a question of convention, not rule. Really, there’s no practical difference between 2/4 and 2/2; you can interchange the two by changing all the note values and doubling or halving the tempo as appropriate. There are also conventions dictating the difference between simple meters and compound or complex meters*; if the “numerator” is larger than 4, the “denominator” will tend to dictate the difference–1, 2, or 4 will tend to denote simple meters, while 8 or 16 will tend to be compound or complex. But, again, those are conventions, and can easily be broken.
Something like 15/13 could easily be 15/8 or 15/4, or whatever. The 15 is the important part.
Now, that said, it can become interesting if you’re pairing it with other meters (say, 5/4) while keeping the whole note length the same. Still, even then, you’re just doing various tuplet lengths and playing around with bar lines.
*Simple rhythms are sub-divided in two, and when written, the top number tends to indicate the number of beats. Compound meters are sub-divided in three, and the top number generally indicates the number of sub-divisions. So 6/4 would probably be six quarter-note beats, each subdivided in two, while 6/8 would usually be two dotted-quarter-note beats, each subdivided in three. Complex meters have beats of different length; 5/8 is usually two beats, one two eighth notes long and one three eighth notes long (5/4 tends to just be five quarter-note beats).
That’s exactly how I know those oddball meters to be used. Lemme see if I can dig up the Straight Dope discussion on this…
Yes. Here’s the thread on it.
I immediately thought of Blue Rondo.
What the hell does a 10th or 12th note look like? I guess you could use a dotted 8th for a 12th, but a 10th?
Murray Gold’s theme for the Eleventh Doctor is in 7/4. Because 7+4=11.