Gizmodo has a quick and easy hack for breaking the DRM on the Zune's WiFi. The Zune locks the music you wirelessly share with other Zunekers so that it only plays three times before evaporating. This is applied totally indiscriminately, even to Creative Commons music with a machine-readable license granting permission to distribute it. It would also apply this restriction to students who shared MP3s of their class-lectures.
First, you need to enable hard drive mode using the instructions we posted before. Then, rename whatever files–MP3s, movies, programs–to have the extension ".jpg" in order to fool the Zune into thinking its an image. This hack works because Zune doesn't apply DRM to images!
Now, take your Zune and send the folder containing these files to your buddy along with a real photo. If you only send a fake photo, an error is thrown. The last step is to have your friend sync the Zune with their computer, open the "containing folder" where the files were downloaded, and rename the files back to their correct extension.