So this one is from way back when I was a second-year umpire or so. I would have been about 13 at the time.
Umpiring a house league game for 11 year-olds, behind the plate. Since it's house league and a low level, they're allowed to play while fielding only 7 players, but no less than that. Happily, they showed up with 7.
In the second or third inning, this little kid who'd been a problem all year was running in from 2nd on a pretty standard slow grounder to 2B (remember, 11 year-olds, so the throw goes to 1B). BR is out at 1B, throw comes in to home. I get in position, kid drops his shoulder straight into catcher's chest as tag is applied well ahead of getting near home. Our local league has strict rules against malicious contact, and on plays at the plate like that players are required to slide to avoid anyone getting injured.
Kid's out and gone. Parents, who are not-at-all coincidentally also the coaches of the team come screaming out of the dugout at a thousand miles an hour shouting all kinds of unmentionables about me and their up-and-coming Derek Jeter.
Ring 'em up, game is forfeit since they've only got 6 players and, now, no coaches.
To this day I've never had a simultaneously more hilarious and ridiculous ejection.