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The Trevor Project—a nonprofit aimed at preventing suicide amongst gay, lesbian, and transgendered youth—honored Katy Perry (in Marchesa) at the organization’s Trevor Live event in Los Angeles, where actresses and funny ladies Aubrey Plaza and Amy Poehler also attended in support of the cause. Perry, whose songs like “Firework” are often associated with anti-bullying and pro-tolerance movements, was given the Trevor Hero Award for serving as a positive pop culture role model. Click through the gallery to see more stars at the biggest parties of the week.