Warren Buffett and Bill Gates recently launched the "Giving Pledge," which asks America's billionaires to donate at least 50% of their wealth to charity — an initiative that, if successful, would raise approximately $600 billion for nonprofits across the world. Who better to accept the challenge than the richest self-made woman in American history?

Oprah Winfrey's worth $2.3 billion dollars, qualifying her for the Pledge. Currently, Oprah has put 11% of her personal wealth toward philanthropy.

The first black woman to ever reach billionaire status or make the list of America's top 50 most generous philanthropists, Oprah regularly uses her cash to positively impact the world, starting a successful charity (Oprah's Angel Network) and donating $303 million of her own money to various causes. Now the household name has a chance to make history once again.

Ask Oprah to accept the "Giving Pledge" and donate at least 50% of her wealth to charity while setting an example for the rest of the country's billionaires.

Photo credit: emilydickensonridesabmx