I’m sure the majority of readers know about Terry Riley’s “In C”:

Here’s part of the first recording made:

And here’s a more recent recording, talking about the work and showing the musicians rehearsing (including Sid Chen, who blogged about the experience):

And now there’s a clever site called in Bb. Check it out and play around with it! 🙂

So far, I’ve found no “In A-440”.