In general, around 200 nations send athletes to compete in the Summer Olympics. For a country (or territory) to compete in the Olympics, it typically must have a recognized National Olympic Committee (NOC) — a group organized by the competing nation that coordinates with the International Olympic Committee (IOC) to organize their nation’s Olympians. As of 2012, there are 204 recognized NOCs, and each of the corresponding nations will compete in the 2012 London Summer Olympics. Though the Netherlands Antilles, lost its NOC in 2011 when the country dissolved, it will still be allowed to compete. Countries or entities that are unable to compete at the games because they don’t have a recognized NOC include Macau, Gibraltar, Abkhazia, and Niue.
More facts about the Olympics:
The only countries that have never participated in the Summer Olympics are the Marshall Islands, Tuvalu and Vatican City.
As of the 2012 London Olympics, there had been 26 Summer Olympics games held in 22 cities. The only cities to repeat were London, Athens, Los Angeles, and Paris. Berlin and Tokyo would have been repeat hosts, but the Berlin Summer Olympics of 1916 were canceled due to World War I, and the Tokyo Summer Olympics of 1940 were canceled because of World War II. Stockholm has hosted the Summer Olympics once (in 1912), and the equestrian events only of the Summer Olympics (in 1956) another time.
There are 80 countries with NOCs that have participated in the Olympics but have never won any medals, including Laos, Aruba, Oman, Grenada, Turkmenistan, and Brunei.
Each city that hosts the Olympics can expect to make at least $1.2 billion US Dollars (USD) from selling the TV broadcast rights and getting sponsorships.