My 6 year old Chihuahua wont stop barking!?

I have a 6 year old chihuahua. I know they are known for their "yappiness", but mine seems to take it to a new level. She barks when my kids run in the house, she barks when someone leaves or comes in the door. She barks when my kids play too loud. We call her the "fun police" because she "yells" when people are having fun. It seems that barking is as natural and involuntary to her as breathing. How can I curb this barking? I've tried spray bottles of water...but to no avail. Any suggestions?? I don't want to use a zapping collar, but what about the ultrasonic sound collars?