I've used other under-desk headphone holders in the past, but I recently upgraded to IKEA Alex drawers for my desk, and the other designs can no longer clamp onto my desk since the drawers are in the way. 

So, I designed this holder that attaches with a command strip and does not block the drawers. Obviously, the drawers are blocked with the headphones on the holder, but the headphones are easily removable.

Another upside is that since this uses a command strip, it's removable.

Requires:

1 large/standard command strip

Feel free to post your makes if this design works for you!