What sporting event is the most watched in the world?

The most watched sporting event in the world is football (European Football). However, the single most watched event in history was the semi final match between India and Pakistan during the cricket world cup in 2011.

To give you an idea of how popular football is, the 2006 world cup final drew 716 million viewers. While the whole tournament attracted 30+ billion non-unique viewers.

As for recurring events, 600 million households watch the English Premier League (football) a week. Bear in mind that 600 million doesn't include illegal viewers.

For more information, please refer to the related link.