They seem to come from a wall. I've listened to the neighbors noises, and they don't come close to matching. These are very sharp noices, obviously originating form the room. We've turned off computer speakers, made sure things aren't 'shaky'.
It sounds to me like a marble hitting the wall. I tested it. Totally different sound, more muffled. I accedently dropped the marble after hitting the wall, and it hit the desk. THAT was the sound it made, exactly. A marble hitting wood from a highth.
Now, it COULD be wood expanding/constricting due to weather -- however, in the 4 years we've lived here, it's never done it before.
So, is it a ghostly rapping? Anyone got experiance in rapping?