My Computer Makes Noise at 2:34 PM

WTF!? At school I always had my computer on mute so as not to disturb my roommate, yea I can be nice at times. Now however I don't have to worry about that so the sound is pumped up loud and usually playing some kind of really great music because thats how I roll. Well lately its been making really weird random noises. Not like "omg my computer is going to explode" noise but random dings and chimes and such. I always have a bunch of programs open and windows running on my desktop so they could be coming from anywhere. Every few minutes I hear one and get to go on a hunt. It's like playing a game with my computer, looking through all the windows to see if anything has moved or changed. Sometimes I expect to see some freakish monster hiding behind the open window with this look of guilt on his face as though I caught him making those random noises. Seriously its driving me crazy. Cut it out computer. Damn it, it did it again. Where is it coming from!!!???!!