Challenge Fundraisers are competitions where charities and their passionate supporters compete to win prizes from our amazing sponsors. Check out the latest Challenge Fundraisers below and get involved. If you’re a company or foundation or really nice person that wants to sponsor the next fundraising challenge, email us right away for info. Firefox, Groupon, Huffington Post and other incredible organizations have sponsored Fundraising Challenges on Crowdrise. There’s no better way to leverage your charitable dollars.