I really wish there was something like f.lux (http://stereopsis.com/flux/) for iOS, or at least without having to jailbreak and do whatever else, because then I might be able to use my iPad in bed to read a bit before sleeping.

Having it on my laptop had made a big difference -- I "felt tired" when the display temperature was adjusted at nighttime. Before that, I could happily stare at that blue light and stay awake as long as I wanted, at the expense of my productivity the next day.