Playing a often-bullied geek on Glee comes easy to Chris Colfer, who tells PEOPLE he thought of himself as "a walking punching bag," and was "teased everyday from elementary school until high school."
Colfer, who is by no means grateful for being pushed around, says "it really taught me to be quick on my feet. Some of my witty comebacks are legendary."
Gossip Girl's Michelle Trachtenberg has also been physically harassed. "This one girl threw me down a flight of stairs, fractured my ribs, punched and fractured my nose," she told Complex magazine.
But as in the case of Clementi, not all bullying is physical. Simpson, too, was a victim of a different kind of taunting. "[People] would throw toilet paper at my house or throw eggs at my door," she once said.
Adds Alba to the U.K.'s Daily Mirror, "I was bullied so badly my dad used to have to walk me into school so I didn't get attacked."
Standing Up to BulliesBut bullies don't always go down without a fight. Several stars had the courage to stand up for themselves.
Eva Mendes says she put an end to bullying in her life. "When I finally stood up to my bully, that's when things changed for me," she told PEOPLE.
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Demi Lovato is involved with PACER's Teens Against Bullying organization. "People say sticks and stones may break your bones, but names can never hurt you, but that's not true," the Disney star wrote on PACER's Web site. "Words can hurt. They hurt me. Things were said to me that I still haven't forgotten."
Brittany Snow, with the help of the Jed Foundation and MTV, started her own organization last week, in the wake of recent teen suicides. "When I was younger, I was bullied daily, and it led me to face other struggles," the actress tells PEOPLE of her Love is Louder non-profit aimed at drawing attention to issues of bullying and depression. "I know what it's like to feel alone and outcast."
In the end, an important message stands out all of this: There's light at the end of the tunnel.
Ashley Tisdale tells PEOPLE, "I just hope, and I really want to stress to kids that after high school, it's so much better."
With reporting by BLAINE ZUCKERMAN
For more on bullying, see the new issue of PEOPLE on newsstands Friday, and our special week-long series with Anderson Cooper 360, airing on CNN nightly starting Oct. 4, along with a special PEOPLE-CNN-Cartoon Network Town Hall on Fri. Oct. 8 at 10 p.m.
Another resource, which is supported by many celebs, is The Trevor Project, a confidential, toll-free, suicide hotline for gay & questioning youth: 1-866 4-U-TREVOR.