Pass Interference Calls
Officials call pass interference when a player takes certain actions to prevent a receiver from catching a ball. This rule works both ways -- a defensive player can interfere with an offensive player, but an offensive player can also interfere with a defensive player trying to make an interception. The foul must occur after the receiver begins running from the line of scrimmage, and the ball must be catchable, a judgment call to be made by the officials. Defensive pass interference, specifically, can result in some of the most severe penalties of the game, grossly out of sync with others that are five, 10 or 15 yards for other infractions, because the ball is placed at the spot of the foul -- where the player was interfered with. If the pass was a bomb intended for delivery to the other end of the field, this could mean a penalty of as many as 50 yards, or even more.
Pass Interference on Punts
A weird exception exists with pass interference rules when a team fakes a punt, pretending they’re going to kick the ball away to the other team. Instead, a player takes the ball and hurls it to another player who has gotten free downfield. If this receiver is interfered with, there’s no foul under NFL rules because the play wasn’t technically a pass play to begin with.
All Lines Are Not Created Equal
The white sideline areas along its length mark off the playing field. Anything that happens on these white areas, not actually on the field, doesn’t count. If a player catches the ball in this area, it’s not a reception. This rule focuses on the player’s body, not the ball itself. If he hauls in a pass and the ball is clearly within bounds but one of his toes is on the white section, it’s not a completed pass. The opposite is true with the goal line, the line separating the field and the end zone. Here it doesn't matter where the player's body -- or any part of it -- is. The ball itself must move across the goal line for a score. Eighty or 90 percent of a player's body might crash into the end zone, but if the ball itself doesn't "break the plane," it's not a score.
That Extra Point
Another tricky rule involves extra points -- the kick through the uprights after a touchdown so the team gets seven points for the score instead of six. Sometimes it happens that the snap to the holder, the guy who sets the ball in position so the kicker can boot it through, is bad. The ball gets loose. If it begins rolling around the field and a defensive player inadvertently kicks it or otherwise sends it over the goal line and out of the end zone, the kicking team still gets the extra point.
End Zone Celebrations
Unsportsmanlike conduct penalties are a catchall that include physical, tactical and even emotional infractions. Some are designed not to protect players from injury, but from hurt feelings. If a player catches a ball in the end zone and carries on a bit too much in the opinion of the officials -- usually by performing some version of a happy dance -- this can result in a penalty.