From a PBS article:
"Since the Carter Center opened its doors in 1982, it has developed dozens of programs to alleviate suffering and improve lives around the world. Its efforts fall broadly under two categories, "Waging Peace" and "Fighting Disease." The Carters' peace work includes conflict resolution, election monitoring, and the promotion of human rights and democracy. Health programs include agricultural initiatives to eliminate hunger in Africa, Rosalynn Carter's mental health task force, and programs to control or eradicate preventable diseases afflicting the world's poorest people. The best example of the latter is the Guinea worm eradication program, which has so far succeeded in reducing this debilitating disease by 98% world-wide, making it potentially just the second disease after smallpox to be wiped out by human effort. In all, Carter Center programs have reached 65 countries, with the greatest impact on the developing world."
"In 1984 President and Mrs. Carter began working with Habitat for Humanity, a Christian organization based just down the road from Plains, devoted to building low-cost housing for the poor. That fall they journeyed to New York City to rebuild a tenement, where the sight of the hammer-wielding former president caused many Americans to reappraise the man they had voted out of office four years before."
" Though some Republicans remained wary of him, Carter's zeal and his good relationship with President George H. W. Bush's Secretary of State, James Baker, led to peace missions in Ethiopia and the Sudan. In 1994 he helped the Clinton administration broker peace in three dangerous conflicts, traveling to North Korea to arrange a nuclear freeze with dictator Kim Il Sung, to Haiti to persuade General Raoul Cedras to step down before an American invasion force arrived, and to the former Yugoslavia to negotiate a cease-fire between warring Bosnian Muslims and Serbs."