Ugh...Event Handlers

Alright, so I keep hearing people go on and on about these event handlers…and I have no clue as to what they are. (Yeah, yeah, I know…just don’t laugh.) I’ve searched high and low for an understandable explanation of event handlers. And it seems to me that it would help my coding significantly if I could just get a real in-depth, easy to understand explanation of what they are, chock full of examples of course.

Could anyone help me out here, please?