We just can’t get enough of the latest addition to the SIGG family of eco-friendly water bottles. The lightweight, reusable Hello Kitty design, $24, is the cutest way we’ve found to protect the environment. And while many of Hollywood biggest stars, including Madonna, are ardent new fans of the products, environmentally-conscious style is nothing new to the Swiss company, who mark their 100th anniversary this year. To celebrate they’re launching an interactive website, sigg100.com, in partnership with the charity Stop Global Warming, which explores the 100 most significant eco-moments of the past century. Until Earth Day on April 22, you can count down historical eco-moments, chat with other readers, and test your eco knowledge. And while you’re there, be sure to sign up for a chance to win a trip to Oahu, Hawaii for the ultimate in green festivals. Get your bottle for $24 at delight.com.