Army Staff Sgt. Darrell Griffin Jr. was killed in March 2007 in Iraq by a sniper. Courtesy of Darrell Griffin Sr. hide caption

Cellist Alisa Weilerstein. Jamie Jung hide caption

Mark Darrow, a meteorologist at the National Weather Service's Storm Prediction Center in Norman, Okla., keeps watch by looking for evidence of tornadoes, heavy winds and damaging hail. Sue Ogrocki/AP hide caption

Marijuana buds for sale at the Sunset Junction medical marijuana dispensary in Los Angeles, Calif. Kevork Djansezian/Getty Images hide caption

Hand washing at California's Pacific Hospital, especially in the ICU, is now so routine that nurses complain their hands are chapped. Leah-Anne Thompson/iStockphoto.com hide caption

The Splinter Bike, built by carpenter Michael Thompson. Courtesy Michael Thompson hide caption

Daphne Willis' new album is titled Because I Can. Lauren Dukoff hide caption