How many people spend their birthdays volunteering? We'd venture to say not a whole lot. And we'd guess that even fewer people spend their 103rd birthday volunteering — clad in a Wonder Woman costume, no less. Yep, it's safe to say that Mary Cotter is truly one-of-a-kind. And winning at the birthday game. KABC-TV joined the centenarian at the Montclair Senior Center, located east of Los Angeles. She's been volunteering at the center for 25 years. "They call me the barmaid because I'm serving drinks," she joked. As for her outfit? It was a gift from friends, who insist that she is a real-life Wonder Woman. When asked about her secret to longevity, she shrugged and said,"Just keep busy I guess." But donning amazing costumes every now and then probably doesn't hurt, either. Watch the video below to see Cotter in action.