Hayden Panettiere

 Hayden Panettiere Why you know her: She's the invulnerable cheerleader on "Heroes" Why we love her: Not only is Hayden ridiculously cute, she's also willing to put her body on the line to stand up for what she believes in. She famously took to the water to try to disrupt a dolphin hunt in Japan, and has hand-delivered a letter of protest to the Norwegian Ambassador urging the country to end its whale hunts.