Well, the fan made a weird noise once, and I decided to tilt it - a bit faster than I should have. I have only done this a few times, and the times I have, it has had this behavior. Of course I will never ever do this again, adding one more thing to the list of ways I care for my PB (and nixing one off the list of the ways I have abused my Ti). The reason? I had to move it up to plug in a USB plug I was having trouble getting plugged in (normally it is easy enough to do this by feel/touch alone). Long story short, I flipped it up, and, the noise occurred. I did it a few more times, questioning the noise, and heard it again. > Why?????