Melting Asphalt's A Nihilist's Guide To Meaning is a good guide to what constitues a meaningful event.
It proposes that since events cause each other, an event has higher meaning to us if the event is more of a bridging point: the event was crucial or else a lot of other events would not have happened. An event is less meaningful if it's a dead end - it didn't cause many events afterwards.
This is an interesting perspective to view meaning through. If we want our lives to be more meaningful, it could mean that we need to become a part of the chain of events and start more things that would not have been started otherwise.