Bill Gates' New Challenge: Build a Better Condom Microsoft co-founder hopes to prevent disease and unwanted pregnancy around the world. Winter Storm Blasts Midwest, East Warnings, watches or advisories for 13 states in what could be winter's final punch. Two tourists get extreme close-up with great white shark during cage dive. Knox faces appeals court for overturned conviction in 2007 murder of roommate Meredith Kercher. Investigators work to find motive for murder, including possible revenge from prison gang. Winter storm drops foot of snow on Colorado, 15 states under storm advisory. Lucky lottery winner faces giant bite out of earnings with new tax bill. Political strategist says he could imagine a candidate for GOP presidential nomination supporting gay marriage. The iconic New York hot spot celebrates with a hot dog-eating contest. ABC News' George Stephanopoulos discusses the historic event. Spring Snowstorm Heads East Kansas City is hit hard by this never-ending winter.