For tough sports, the Tour De France cycle race takes some beating. The object isn't to kill your opponent, but you come pretty close to killing yourself.
But I'm less interested in games involving people beating the shit out of one another, and more interested in games involving skill.
Football, as most countries in the world call the call the game with the spherical ball, which you kick with your foot, will always be the beautiful game to me. If you've grown up with with a game, supported your team through thick and thin, through bad times and good, it's like your best friend. Liverpool is my team. I love them like Scottish Robbie loves Celtic. With a passion. Nothing better than watching the movement of your team when they're playing at the top of their game.
But I can accept that the appeal of football, or sometimes sport in general, will always remain a mystery to some people.