Sometimes in the car or when we're cradling DS, he'll look up and off into a corner, and just smile and/or coo for a good few minutes. We look towards that vacinity and don't see anything ourselves so we're always curious what is capturing his attention that much to cause him to smile and talk! I sometimes plug in, WHO or what, and it creeps DH out. haha!
Does your LO stare off into space and randomly smile and talk?