Big Idea: http://LiveBelowTheLine.com/ is an international challenge and social media campaign that asks participants to live below the poverty line, on a budget of $1.50 per day for five days.

Why It’s Working: The challenge is in its infancy, but it has already seen 25,000 users take it on, including celebrities such as Josh Groban and Malin Akerman. Funds raised through Live Below the Line have gone to many international charities focused on hunger and the developing world, including UNICEF and Malaria No More.