Rugby World Cup

It would go to a 'Kicking Cometition' (place kicks). Much like a penalty shoot out in football. It is not very fair as you could end up with a prop taking a kick to win.

RWC Rules 2011 says -

Kicking Competition

If at the end of a knockout match, after extra time and sudden death periods of play have been completed, the teams remain tied, then the Referee will conduct a place-kick competition to determine the winner of the match.

The following procedures apply:

1. All Players and Match Officials will remain on the playing enclosure. The Referee will call the captains of the two Teams to the centre of the playing enclosure and will conduct a coin toss. The winner of the coin toss will choose which Team kicks first.
2. Only Players on the playing enclosure at the time of the completion of the sudden death period may take part in the kicking competition. For the avoidance of doubt, no substituted (including for injury and/or blood), ordered off or temporarily suspended Player not on the field at the completion of the sudden death period may take part in the kicking competition at any time. The five Players selected and the order in which they kick do not have to be specified at the start of the kicking competition.
3. The Match Officials and Team Members will assemble on the halfway line. Team Members must remain behind the halfway line in the side of the playing area not being used for the kicking competition. No one except the Referee, two Assistant Referees and two ball boys is allowed in the part of the playing area being used for the competition.

The five Players from each team will place kick from three different areas, all on the 22 metre line, as follows:

1. First area: directly in front of the posts
2. Second area: on the 15 metre line on the left hand side of the posts (determined as facing the posts)
3. Third area: on the 15 metre line on the right hand side of the posts (determined as facing the posts)

The Referee will start the competition by calling the first Player selected from the team kicking first to the first kicking point. Once the Player has taken the kick, the Referee calls a Player from the opposing team to kick from the same area.

The next two Players (one from each team) will kick from the second area in turn. This will continue until all five Players from each team have kicked (the next Players kicking respectively from the third area, first area and finally the second area), or until one team is unable to equal the score of the other team within the remaining number of kicks.

If there is an equal number of successful kicks once each team has completed its five kicks, the competition continues on a "sudden death" basis, following the same order of kickers used in the first five kicks.

The competition will continue two kicks at a time (one from each team), going progressively through the three kicking areas stated above (and repeating the process if necessary) until one Player succeeds with a kick and the Player from the other side taking the same kick misses it. Once this occurs, the team of the Player who succeeded with the kick will be declared the winner.

Throughout the kicking competition:

• Players must be nominated immediately on request by the Referee. Once a Player has been handed the ball on the kicking area, he must take the kick within one minute. Should he take longer, the Referee shall declare the kick void.
• After each kick, the Referee will record the number of the Player and whether or not the attempt was successful. The Match Commissioner will record the same details on the official match Report.
• Whether or not the kick is successful is the sole decision of the Referee, who may at his sole discretion rely on the assistance of his Assistant Referees and/or the TMO. The Referee's decision shall be final and binding.
• Once a Player has completed his kick, he shall return to stand with his team behind the halfway line in the side of the playing area not being used for the kicking competition.