Make a random choice on collision enter - c#

Hi there, being new to Unity I'm struggling to find a good way of doing the following.

On collision enter of a certain game object, I want either a random script to be enabled (from a set of scripts I define) or put all the scripts in to one file and a random choice of which case to use is made.

Does anyone have any pointers or code samples of how I could achieve this? preferably in c#.