Most people's bucket lists include things like traveling to exotic places and reuniting with long lost friends. But philanthropists have harder decisions to make. In 2007, when Denny Sanford donated $400 million to the Sioux Valley Health System, of Sioux Falls, S.D., he turned to a panel of experts to decide how best to use the gift. His requirements were simple. The project should address a disease of relevance to the population of the region, and should cure it within the 73-year-old philanthropist's lifetime.