This happened when I was about five or six years old. My sister and I were in our bedroom one night, and I was playing with a toy phone. Just a little plastic thing. Might have even been my baby brother's. I said hello into the receiver and clearly heard a man's voice say hello back to me, right into my ear. The voice wasn't creepy or ghostly; it sounded like the normal friendly way an adult would say hello to a little kid. But I was still terrified, of course, and ran to tell my parents. I even asked my dad if he'd just said, 'Hello,' but he hadn't. Honestly can't remember what they said after that, but probably something reassuring.
As I got older, I kept trying to tell myself that it was just the normal active imagination of a kindergartner. Even though my imagination had always been just about 'playing pretend,' with dolls or toys or friends or whatever, but fully aware I was just playing, as opposed to seeing or hearing things that weren't there. But I can still hear that voice in my mind. (Fifty-five years later!) It didn't sound like anyone I knew, and I never heard a voice on that telephone again. Come to think of it, I was so spooked that night, that I probably never played with that phone again! But for some reason I've always wanted to know if anyone else had ever had that same experience, toy phone and all, or something very similar. Since unexplained things like that have been pretty rare in my life, when they *have* happened, I guess they tend to stick with me. Half of me tries to find a logical explanation, and the other half is just weirded out for a very long time.:)