You probably think you've already heard all the Windows noises (chord, beep, ding, etc), and that there's nothing more to hear. You're wrong: listen to Windows Noise Becomes Music. Using the Windows sound recorder to play back the built-in noises in different ways, and combining them together, he's created quite a musical composition. (I'd point to the author's own site, which has other cool Flash gizmos, but it has exceeded its bandwidth for the month.)