Sport Relief is a charity event that uses sport to raise loads of money and help improve people's lives.
The first Sport Relief kicked off in 2004, and a second event was held two years later. So far more than £20m has been raised for good causes.
This year, Sport Relief is taking place from Friday 19 March to Sunday 21 March.
The highlight of the weekend is the Sport Relief mile, where many thousands of people will run a mile for charity.
The charity is part of Comic Relief, and like the famous red noses sold to raise cash, Sport Relief has a similar item - red socks.
Loads of celebs will be wearing those red socks as they run their Sport Relief mile, and there's plenty of ways that kids can get involved too.
Lots of other people from other shows are also getting involved in 2010, including Blue Peter's Helen - who is kayaking the length of the Amazon River!