Jessica Biel looked stunning on Monday night in Valentino as the host of the charity: water Ball at the The 69th Regiment Armory in New York City. The philanthropy aims to bring clean drinking water to people in developing nations. She spoke exclusively to InStyle about what she finds most surprising about the organization. “Everybody that works there, they are the greatest thinkers with the most out-of-the-box ideas, the energy is unstoppable and never-ending, and it’s fun!’’ she explains. But if you’re motivated to change the world on a smaller scale, Biel has some advice: “If you can pinpoint one or two things that are most enjoyable to you, and focus on that, whether it’s, 'I’m going to recycle and I take 5 minute showers,' then leave it at that! And when it starts to just become organically part of your life, then you add on another bit, and then eventually, it's just part of you as a human being.” She also rounds up her favorite red carpet look of the year, only for InStyle. Click through the gallery and tell us, which one is your favorite?