I was about to start on a show in a big London vfx house as a ligting TD using Mental Ray so I did this as a test to brush up on my skills/knowledge with that renderer.
I grabbed a model I made a few years ago which is a part of a car's suspension rig, and a HDRI I created with my Nikon D70, a chrome ball-bearing and HDRShop and spent no more than a day to try and get a nice render out.
I also added grain and a tiny bit of bloom in Nuke, besides that there is no post work.