What is the record attendance ever for a sporting match in an enclosed stadium (ie not a racing track)?
Answer: The 1950 soccer World Cup Final between Brazil and Uruguay at the Estadio Maracana, Rio de Janeiro. A colossal 199,854 people are recorded to have watched the game, and some estimate that the actual attendance was 205,000 when non-paying attendees are included.
Source: The World’s Game by Bill Murray