Improvements to the holodeck
I've intentionally been sleeping a little more than necessary the last three nights, and last night as I laid in bed, I tried to just lay there and relax, but not let myself fall asleep. Every time I felt like I might lose consciousness I changed my position in bed to help stay awake.
I did this for a while, only to learn one thing. At some point I wasn't "awake" any more, at least not like you and I normally think of being awake. I was awake inside a dream, what I call the holodeck. The bed, the room, everything, was just as real to me as the computer I assume I'm typing on right now.
In this state, even though I'm awake, functioning, and consciously making decisions, there is still something in the brain that doesn't make you question the reality of what you're seeing. For instance, in dreams it's common to look at something once (something like a table) and see one thing, and look at it again and see something else, either subtly different, or completely different. In the holodeck last night I may have had that problem, but frankly, there's nothing that comes to mind about what was different from my normal room. As far as I knew, I was awake, and trying not to fall asleep.
I finally realized I was in the holodeck when I started to fall asleep, and could feel the vibrations starting. It felt like there was something wrong with the vibrations, and as I started to think about things, something in my mind realized I was actually already asleep.
At that point I did what I normally do, wake up, and go back to sleep. In the future I'll try not to wake myself up, but the surprise, disappointment, and mild shock are usually enough to wake me up.