I wrote a little Prelude tonight in Binary form to exercise in modulation. The first half is in C major and modulates to the dominant G and closes, then the second half starts in G and modulates back to the tonic C major and closes, as is standard modulation in the baroque binary.
Click --->
http://www.nonstopsportstalk.com/Prelude3.mp3
The piece above reminds me a bit of an older prelude I wrote, so I'll post it. It's also in C major. I think this one is better, and has a lot of fun hand crossing.

Click --->
http://www.nonstopsportstalk.com/PreludeC.mp3