Las Vegas Sun: Scores of casino-hotels and other businesses and organizations on and off the Las Vegas Strip have committed to show their support for the environment by participating in “Earth Hour” on Saturday night, when they’ll dim or turn off their signs and decorative lighting for an hour to raise awareness about climate change. The event, organized worldwide by the World Wildlife Fund, lasts for one hour beginning at 8:30 p.m. Some 2,500 cities globally are participating. Among the …