Rule of the Week - The Infield Fly Rule

So this didn't happen in this week's game, but it seems to be the most commonly cited arcane baseball rule. So here we go:

The Infield Fly Rule

When less than two outs
Force at third, fly to infield
Ump calls batter out

• Recap: N/A
  
• Explanation: Rule 6.05(e) with a definition in Section 2.00. I'll use the Wikipedia summary here:
  

  The infield fly rule applies only when there are fewer than two outs, and there is a force play at third (runners on first and second base, or bases loaded). In these situations, if a fair fly ball is hit that, in the umpire's judgment, is catchable by an infielder with ordinary effort, the batter is out regardless of whether the ball is actually caught in flight. The rule states that the umpire is supposed to announce, "Infield fly, if fair." If the ball will be almost certainly fair, the umpire will likely yell, "Infield fly, batter's out!" or just "Batter's out!" Umpires also typically raise one arm straight up to signal to everyone that the rule is in effect.

• Enforceable: N/A - I'm not sure how you could mess this up, since the ump is going to call it. Perhaps the ump owes a pitcher if he messed this up?