There are two rook plus pawn vs. rook positions that every player should understand: the Philidor position and the Lucena position.
You will sometimes get positions very close to either the Philidor or the Lucena: in many (most?) cases, your job is to try to convert to the Philidor (as defender) or Lucena (as attacker).
In round one of the U.S. Open, Sevan Muradian handled the ending much better than his young opponent, but made one slip that could have thrown away the upset win. Very nice game!