Last semester before I quit French (I could never get past the different tenses of verbs :() we went through an entire class without learning anything because at the beginning of class, our teacher told us that "happy" in french is "bonher", or somewhere along those lines. It's pronounced bon-air but we couldn't get through the class period without making remarks towards it.

Also when we learned what vacuum cleaner was in german. We were like "wtf?" xD