An aspie is one who has Asperger's Syndrome, which is believed to be part of the autism spectrum. Aspies, while being quite gifted verbally, have social, emotional, and sensory integration difficulties, among others. Aspie is an affectionate term, and is not meant as a put down.
My son is an aspie, so he's not so great at making idle chit chat at parties, or even at being in crowds, but he can get us home from anywhere. He says he just consults the map in his brain.