Many times when having the wakeup problem, a violent shaking of the unit sometimes brings it back up. I also believe it is not asleep, but rather "Dark" i.e. no backlight. i say this because many times if I tap where i am pretty sure the key is the IR gets emitted and the unit lights up.

To recap, I pick up the unit hitting the side button to turn it "on" does not work. the voluime scroll does not do anything, Randomly tapping the touchscreen some times does the trick, violent shaking sometimes does it, blindly hitting an active (button) spot on the screen sometimes does it.

I sometimes wonder if there is a way to keep the backlight on all the time when using the unit and then shut it off when I plug it in the charger. That would be a nice option and be much more friendly to non "pro users" such as guests. In that vein i wonder what the battery drain would be if the backlight was always on.