Leukaemia and Lymphoma Research has launched a new fundraising platform that aims to revolutionise the traditional sponsorship model for charity challenges.
The blood cancer charity said the site, called Pledgeit, is the first crowdfunding website to be built in-house by a charity.
Instead of someone deciding to take on a challenge and then ask their friends and family to sponsor them, it allows people to challenge their friends to do something, such as write a book or try stand-up comedy.
Friends and family can then contribute pledges through the website to encourage the nominated person to complete the task, but the money is only taken once they have done it.
The site is integrated with the social networking website Facebook, which means a person can only be challenged by a Facebook friend.
Cathy Gilman, chief executive of the charity, said: "The financial environment for fundraising has never been more challenging.
"Our response is to focus even more resource on creativity and innovation to inspire and engage people in raising the money we need in ways that are relevant and enjoyable for them."
All the money raised will go to Leukaemia and Lymphoma Research.