I am trying to keep this site from just being a collection of that awesome thing I found on the intertubes, but this is too cool to not pass on.
It's called In Bb 2.0, and it is a collaborative music project. I will embed a few of my favorites. Just play a few of them at the same time and see what you get.
This brings out the composer in me. The sad, little, shriveled, talentless composer.