Need help changing materials on tap

I'm trying to find a way to cycle through a list of 2-6 materials for one object after tapping it. Either that or have it switch to another version of the same object that has a different material on a tap.

To be clear I need a pair of sunglasses that can change colors after you touch it. I have tried to follow all of the tutorials I can find online but nothing seems to work. I'm way too new at scripting and don't know how to fix the errors I get. Can someone help me write an easy script that I can save and use over and over again?

Thank you smart people!