I recently checked out The Volley Cam, an easy to use tool to record play on court, whether a lesson or match.
Turn on the camera, hang the mounting tool high on the back screen (or curtain), adjust the viewfinder using the mirror and off you go. You've got the court under surveillance.
The system comes with instruction on how to use everything including uploading your video to various platforms for review.
The tool itself is a work of a true MacGyver; it'll turn heads for sure but it's well thought out and easy to put together. Once set up, it's solid and works well.
The Volley Cam is $245 complete with a Kodak sport camera or $125 with a VolleyMount for camcorder or cellphone.
Find it at VolleyCam.com. Here's their commercial video: