How to make objects "Bounceable"

Hey Guys I have this problem:
I wanted to add Physics to an object the Player can jump on and when he does the object goes down a little, so that we have this realistic effect.
I played around a little with the diffrent Joints from the Physics pannel but it doesnt seem to work out right like I want it. If you can help me somehow, please answer -
Thank you

This cant be solved by simply a hinge joint. A charController never interacts with physics. This is just possible with a Script attached to a trigger around that object that says: onTriggerEnter add force/mass and onTriggerExit return;

Just a Joint is cool when the object that will collide with it, is not a CharController. Otherwise, just a OnTriggerEnter Script will help.