"The women hunt, and they build the houses," says Simpson (with a mother and child in a Masai village near Nakuru). The hut "is not mud. It's actually cow dung. Interesting, right?" Via cell phone, she described to husband Nick Lachey, 32, who was in Sweden recording a new album, how she was roughing it. "I told him, 'Nick, you would be so proud of me. I had spiders in my bed, and I didn't even care because I was so tired.' "