When I was younger, often "falling" asleep felt like literally falling. I'd slam my arms down on the bed to "catch" myself, and shoot straight into a panicked awake state until my heart was ready to sleep again. I'd usually have memories just as described, weird combinations of the physical reality of my bedroom with random dream-stuff. I've also felt this on airplanes, not able to fall into any deeper level of sleep but fast-forwarding through time in a semi-aware state.

I did have some really interesting ideas, but usually without writing them down they are forgotten, so I tried that for a while. Can't say I ever thought of anything actually useful this way though, or ever thought about doing it to myself on purpose.