Today began the most popular sporting spectacle in the world, but most of us in the United States barely care. And that's sad. The World Cup is a truly global tournament that allows competition between individuals of wealthy nations and poor nations. Soccer is a great sport because all that is needed to learn how to play is a ball and some flat space. Shoes are optional in some parts of the world. No fancy equipment, no ice, no smooth hardwood floor, none of that is required. As a result, you see countries like Tunisia, Ivory Coast, Paraguay, Ukraine, Trinidad and Tobago, and even Togo compete against European and S. American giants. No other sport is as universal, and in the case of the World Cup, no other event displays such expressive patriotism. The Olympics are close, but they don't match it.
As for why Americans don't like soccer nearly as much as the rest of the world, it's partially because we have other major sports, but I believe it's also because we like to see lots of points or goals scored and soccer can be deficient in this area. If one lengthens her/his attention span and tires to appreciate fine passing, defensive play, and ball-handling skills as well as the strategic aspect, one will begin to appreciate soccer, the world's sport of choice.
If you're an American, give the USA some support! They have a very competitive team this year.