Fairly regularly, my N1 seems to lose calibration or something. When I tap one part of the screen, it seems to click on another part. It seems to be random, but the same random spot. e.g. when I click the same spot it affects the same place somewhere else on the a screen. But it hasn't obviously moved down, or rotated. e.g. I can be typing on the keyboard, most of letters will work perfectly, but then a few will not work at all and another few will type the wrong letter or click on part of the screen above the keyboard.