June 22, 2009 8:12 pm Michelle Obama's Speech on Volunteering The First Lady addressed a crowd at a conference in San Francisco devoted to promoting volunteer efforts. US & World Videos 0:26 Crews working to repair water main break in Richmond 1:29 Teens and tweens struggling with mental health, study says 1:29 Livermore author shares foster care experience 2:42 Hearing on antisemitism in schools 2:04 2 students taken to hospital after difficulty breathing at San Jose school