unevent

1) an event that was poorly planned or was seen as being uninteresting so no one shows up for it.

2) any event that goes unnoticed. As compared to a non-event where people show up for the event, but the event is seen as dull or boring.

3) the opposite of an event.

So did you hear we planned this really big party for saturday night and no one came, it was a total unevent