Multiple times. Twice by my parents, who just laughed it off (My dad poked fun for about a week -_-) and a few times by my roomates. My favorite instance happened last year. My roomate knocked, but i couldn't hear due to the headphones. He then opened the door and made the most unearthly noise I've ever heard in my life. it was something like, "Hey do you know wher- Gnyaaaaaraaa.....". Needless to say, we never talked about this again.