In my younger days, I used to be uber-creative late into the night. Working until 3 or 4 in the morning sometimes on recordings, songs...whatever. There was always something about working late into the night/morning that was always intriguing and inspiring.
Of course in the last 10 years, I have found myself waking up early ( I mean like 3am sometimes) to work on my music. I don't know, maybe it's because I am getting older, maybe it's because I have kids and I'm usually wiped out around 9pm the night before, who knows.
Either way, this is now my routine and I have disciplined myself to wake up at least 2 hours before I need to get up normally. This has resulted in being able to revisit older projects, fleshing out demos for older musical ideas that I know I would have never have been able to get to otherwise.
I find it curious when I talk to my fellow musician friends and see their musical workflow and it always seems to be the same "yea man, I was up until 2am working on stuff". I think that is cool, but I have found that I am personally more productive as soon as I wake up. Which I find funny, because I was never a morning person, but like I said in the last 10 years, I have found the hours right after I awaken, more inspiring and more productive than any other time of the day. Maybe it's because I am still half-asleep and I am not using most of my brain yet, but I think there is something to be said about it.
In final, if you're a musician, artist and/or a creative person and have found yourself in a rut or have a writers block, try and change your work schedule. Set your alarm for a few hours before you should normally have to wake up and I think you'll find some magic there.