Watsi.org is one of the most impressive non-profits I've seen and also the first to go through the ranks of Y Combinator. The work they're doing to crowdfund life-changing medical care for anyone in need for as little as $5 at a time is absolutely awesome.
How awesome? 100% of every donation funds medical care and the org is so dedicated to complete transparency they've got a live public spreadsheet online with every financial record.
Meet the future of philanthropy. With accountability like this, you'll never drop another nickel in a random jar.