Dirty deeds done to sheep [Editor's Note: Weird Al Yankovic actually did make a song called "Dirty Deeds Done to Sheep" so it's not really fair to call this a mishearance]
I was 14 when my high school had its first dance and I asked the hottest girl in the school to go with me. This song came on, and I was singing while I was dancing, and of course, she was a huge AC/DC fan. I said the above lyrics and she just laughed....then fell to the floor laughing, everyone else started to laugh, I couldn't understand why they were laughing, and finally my friend pointed it out to me.