Handler revealed that she went to Germany with a camera crew to find out about her grandfather, a German soldier during World War II. "I don't have a problem with people knowing that I'm part-Nazi, because I'm a part-Jew, so I figured it was a perfect combo ... It's not like I'm gonna find out some terrible thing ... It actually turned out much better that I thought, and I got to see parts of the world I hadn't been to, so that was exciting," she continued.
You can learn a little bit more about the next episode of Who Do You Think You Are? at http://www.tlc.com/tv-shows/who-do-you-think-you-are/videos/sneak-peek.htm although the video there promotes all the episodes, not just the one with Chelsea Handler.