Football at the Olympics is a lot like the World Cup, but with fewer teams.
In the men's event 16 teams will play to succeed Cameroon as the Olympic champions.
There is a special rule for the Olympics, as most players in each team must be younger than 23. However, each country can select three 'overage' players who are older than that.
In the women's event there are 10 teams and the only restriction on players is that they must be older than 16.
Who are the British hopes for Athens?
Strangely, there will be no team representing Great Britain at the Games.
It's all to do with politics.
The home nations play as separate countries internationally, so it would be tough to pick a British side.
Also, if there was a British team in the Olympics then some people might ask why we play as separate countries the rest of the time.
Few fans want to see a British team replace the separate home unions, so Britain chooses to stay out of the Olympics.
However, should London win the right to host the 2012 Games some sort of deal may be worked out to make sure a British team could take part.
Who are the big stars?
In recent years African countries have enjoyed much success at the Games, with Cameroon and Nigeria the last two winners of the men's event.
Women's football has only been an Olympic sport for the last two Games, with Norway winning in Sydney and the US in 1996.
Football is a massive sport in the US for girls, and their team always does well at major championships.