On June 26, 2012, Forbes hosted the "Forbes 400 Summit on Philanthropy," gathering 161 of the list's members to talk about how they try to use wealth to change the world. The day's highlight? A roundtable with six funders who have collectively pledged or given over $100 billion to charity, Leon Black, Warren Buffett, Steve Case, Bill and Melinda Gates, and David Rubenstein. Watch the excerpt, or the linked full video, for their take on how to give back effectively — and why it’s important.