Question on Event Causation

Some of you philosophically-minded types who hold that event causation (understood as a relation between two distinct events) is the primary sort of causation can perhaps help me here. I'm currently working on a paper that touches on issues of event causation, and want to make sure I don't do anyone any injustice. I can understand someone thinking that causation is an event (I think so myself); but why would one think of causation as a relation obtaining between two distinct events? Such a view rules out any possibility of causation being something that is done, because events don't do anything - they just are, and come before and after and during each other. So causation can't be an act or action, even a relative one. Second, if causation were a relation obtaining between distinct events, what about the relation prevents it from obtaining between things other than events (e.g., substances, or numbers on a number line, and so forth)? Third, what reason do we have for thinking events can be distinct objective entities rather than just arbitrary intentional markings-out of regions of spacetime?