Who uses it: Football players and sportscasters
What it means: A football team has four tries, or "downs," to move the ball ten yards toward the goal line. "Third and long" means that the team is on its third try with more than ten yards to go; these are the situations that often turn the game.
How you can use it: At any critical juncture -- if you're the kind of person who applies sports metaphors to real life. In other words, please don't, unless you're actually playing football.
In fact, now that it's the end of the football season, can we please declare a moratorium on football metaphors for a few months? The metaphor load gets a little ridiculous, between the war metaphors piled on football and the football metaphors piled on business. Sorry, sportscasters: quarterbacks are not generals, games are not battles, players are not soldiers. There's a real war going on, and you can't compare a bulked-up millionaire to a 19-year-old earning $20K/year in the service of his country. Get over yourselves.
Thanks, I needed to get that off my chest. But my thoughts and prayers today are with my friend Steve Lechner, who has been a Seattle Seahawks fan since he was a boy. For Steve, as for many fans around the country, I know this is more than a game, and I respect that, even if I don't really understand it.