Rock stars of the world are uniting this weekend to highlight the problem of global warming. It's an extravaganza called Live Earth.
The 150 best musical acts in the entire world will headline the concerts. In addition, there will be 10,000 other events in more than 130 nations, on every continent -- happening at the same time, connected to Live Earth. It's a big undertaking -- as big as hosting 10 Super Bowls, at once.
Madonna is singing a brand-new song in London; Bon Jovi and Kanye West...Full Story