2 summers ago I worked at an amusement park, and got every single person to believe I was British. (I'm not.) It got to the point where even my bosses asked me what life in England was like. It was actually sad, because I'd meet guests in the park who'd ask where I was from in England. I'd say I was from Liverpool, and one lady asked if that was in Germany. I asked where she was from and she told me Texas. I asked her if that was in Canada and she laughed and asked me if I was stupid.
Anyways, on my last day I completely dropped the accent. Everybody was mad at me and I thought it was hilarious. I don't know if this counts as a rumor, because I started and maintained it myself, but it's still pretty funny to me.