This is a lightweight frame to hold your GoPro Hero3 camera. It's not protective like the acrylic housing, but it does allow you to plug in a USB cable so you can power your GoPro for extended time lapse shooting.
See the blog post for more info: http://rasterweb.net/raster/2012/12/31/gopro-hero3-frame/
Print it on your 3D printer and put your GoPro Hero3 camera in it.
Use the OpenSCAD script if you want to make any changes.