Ok, I'll try this immediantly. I already had rigidbody's for the meshes, I'll go and add one to the FPS camera child.

What you are asking is actually easy, but can't be performed with a script that one would be able to cut & paste here.

What you need is basically to:

1- create a gameobject as a child of the main camera
2- attack an fps controller and a rigidbody to the object (so that it has physics). the controller is part of the standard assets.
3- import your scene in the form of meshes and drag them into the scene
4- assign rigidbodies to each of the objects you desire to collide with, and tweak their physical parameters. The tricky part here is that you most surely need to create a script that detects a Collider Hit, to apply a force, that you need to attach to both player and objects
5- bump away