My parents bought me a little plush Pikachu, about five inches tall but very fat, with a cord attached to the top. I fastened it to my rear-view mirror, which provided maximum cuteness with minimum loss of visibility. One day, a friend of mine who was into anime was riding in my car, and noticed the Pikachu almost immediately. "I think I've seen this before. Is this the Pikachu that squeaks when you squeeze it?" he asks.
"Well, I don't think so; I've never --" starts my reply.
He squeezes the Pikachu. *SQUEAK!*
"Wow," I finish. "I never knew that." The squeak didn't sound like anything that Pikachu would make, but it was still pretty good for a non-battery-powered toy.
Years later, the squeaker still works. To this day, this has been the only instance where a fanboy has actually proven to be useful for something. ;)