Robert Bruce is his book mentioned that OBE is easier to do when we're tired. I just proved this right today.

I didn't have any sleep until about 3pm today and as I crashed to bed after finishing some work (and play) just minutes later - without attempting to OBE) I started to feel vibration starting from my solar plexus and chest. I felt my consciousness/astral body start to lighten and drift up from my body about a meter away, while I suppress my excitement/fear - then I see some kind of bluish (?) image but it was blurry I was tempted to look and come closer - so hard I tried to see that I bloody opened my right physical eyes to take a peek and damn I'm back on my body again. It's hillarious when I think about it now (IMG:style_emoticons/default/blush2.gif)

The vibration was still there, buzzing a bit weaker but I was pissed and simply go to sleep not bothering to try again. Better luck next time (IMG:style_emoticons/default/sad.gif)