WASHINGTON (AP) - Michelle Obama dropped in on lunch and circle time at a Washington child care center on Wednesday and used the occasion to announce a new national initiative to encourage child care centers to promote healthy eating and exercise habits starting with the littlest Americans. The first lady watched as toddlers ate a healthy lunch of fish, fruit and salad greens, did the bunny hop with youngsters in a P.E. class and clapped along with singing time at CentroNia, a bilingual child care center that stresses just the kinds of healthy practices that Mrs. Obama is trying to...