An alternative to expensive anamorphic lenses and adapters.
This thing appears as a filter which we place in front of the lense, the line vertical in the center.
You can control the effect by changing the size cutting, the width and the depth of the line ; and, for sure, the glass quality.
The result is more "anamorphic" than a 2star filter (according me).
I tried too with a clean 2mm plexi, and the result is better than CD case.
Tested here with Canon EOS 7D & 50mm.
Picture of the plexi video result : http://tiny.cc/YkIWe
Update : Don't forget to crop your video in 2.35:1 or 2.39:1 !