This Sunday: Michael Phelps and more

It's a heartbreaking case the whole world is now watching: A father's fight for his child. For four long years, David Goldman has been battling to bring his son Sean home from Brazil. After we first broadcast his story in January, there was a groundswell of support -- and growing hope that Sean may soon be allowed to return to the U.S. But the other family involved in this custody case is speaking out, too. NBC's Meredith Vieira brings us the latest. Check out web-exclusive videos of David here, and read a blog from the producer about David's reunion with Sean here.

Also: Actor and Activist George Clooney always draws a crowd. But now he's drawing attention to some of those who need it most: the refugees of Darfur. The very word "Darfur" itself has come to remind us of the depths of human suffering and courage. Now Dateline's Ann Curry travels with Clooney to the refugee camps in neighboring Chad, where people are still waiting for justice. The latest on the humanitarian crisis, and hopes for justice. (See a preview at anncurry.msnbc.com and check out some of Ann's photos from Darfur here)

And finally, Michael Phelps speaks out in an exclusive interview. The swimmer struck gold at the Olympic Games, and then again with multi-million dollar deals as a product pitchman. But last month, when a single photo surfaced appearing to show him smoking pot, his healthy, All-American image went up in smoke. So what was he thinking? NBC's Matt Lauer asks him. photograph of him allegedly smoking marijuana made headlines around the world. Preview the exclusive interview here.