Well, I had some ideas for some music related scripts I wanted to make for programming practice and music practice purposes.
My first was something where you would really easily be able to hear and create complex polyrhythms. The idea was that you could define a time interval and then create different tracks, each with a noise, each playing a tone at a certain division of time. So, say your time interval is 2 seconds (rather long for most musical purposes but stick with me), and you wanted to hear a piano playing an A 4 times during that interval and a clarinet playing a C 3 times during that interval.
Well, with and MIDI sequencer, working with 4 over 3 (anything really related to 2,3,4, and 6) is fairly easy. The example I was talking about would look like this on a piece of sheet music.
Actually, as complex and potentially difficult as that can seem, that polyrhythm is found fairly commonly in music.
One famous example among piano players is in Debussy’s first Arabesque. The main theme features triplets over duplets and is the subject of much suffering for many piano students. However, it is certainly not impossible, and with practice, the rhythm becomes quite natural!
That is far from being the only case (Beethoven frequently changes from duple time to triple time within sonatas, Lyapunov’s etude 6 “The Storm”, Scriabin’s first prelude from Op. 16 has a particularly tricky case due to the accentuation in the left hand, 1812 overture with the measure of supertriplets in the climax, many cases!)
Actually a good exercise that I frequently do on the piano is to start major scales in both hands, with one doing the scale in 2 (or 4) and the other in 3. So one hand will end up doing 3 octaves and the other doing 4, coinciding perfectly at least at the start and end.
The reason I wanted to make the program was because I wanted to extend this thinking into other fractions. As someone will quickly find out upon sitting at the piano, this can be kind of tricky!
Not that this is at all a new idea. Chopin did this stuff all the time. Actually, he did this to quite a wild scale. Check out this excerpt:
11 over 6 and 22 over 12! You can find many examples of this.
At the end of op. 27, no. 2
My point is that these things are very cool! When played precisely, they give a really cool almost clockwork sound (depending on the piece of course) that seems superhuman or at least some form of transcendent.
When I first heard Khaikosru Sorabji’s music, I realized that a lot of his magic comes from his creative use of rhythms. Those unique and exotic textures are created just as much from his rhythmic experimentation as his tonal experimentation.
Check out this excerpt from his first sonata.
So my whole point is, that as a person who likes to play music, I wanted to make this easier for myself.
Luckily, a bit of googling showed me that someone else with a little more programming prowess had already came up with a solution. Actually there were quite a few. If you were willing to pay, there is Bounce Metronome (link). I liked that program quite a bit and am still on my free 30 day test drive 
I also have done some Ruby work in the past so I was able to use the results if a Ruby Quiz. (link) The cool thing was that they gave you all the code so it is very easy to vary to suite your own needs.
The rest of what I found out there were just people who manually programmed their MIDI in certain polyrhythms. Not much control out allowed with those and when exported to something like Noteworthy they end up looking kind of yucky (as in, approximating with 16th and 32nd notes! -depending on your settings of course).
So my newest goal now is to be able to play smooth scales in 3 and 5 at the same time! There is something about 5 time that I just really like. It could be the inherent instability to it that resolves nicely to any other time (though best with 6). For example, there are quite a few examples of songs where the verses are in 5 time but the chorus is in 6. Yes! Even heavy rock too! Songs by Thrice and Dir en Grey do this to great effect. Anyways, I really want to get the ins-and-outs of five time and would certainly love to hear about any pieces in 5 that you enjoy.
Another thing I want to do is really be able to do more rhythms than just straight polyrhythmic beats. Like this:
I don’t know the technical way to describe it but I hope it makes sense. Ha when I try to do this stuff, I normally just write down all the fractions, obtain numbers relating to when I have to play things, and then play it a bunch of times until it actually is what is written.
Do any of you have tips or things that you do for playing these kinds of interesting rhythms?
Another interesting place to hear examples of polyrhythms is in the music of Meshuggah. If you check out their song “Bleed” (here) you can hear the vocalist singing in a meter independent of the guitars and around 1:40, you can hear a really cool interplay between the bass drum and the instruments.
Actually, a new program I want to make would be to aid in the creation of Math Rock, but that is a whole different post for a different day!