I was laying on my bed attempting a wake-initiated lucid dream. I saw what I believe is the beginning of the transition from the waking state to the dreaming state as I began "vibrating", seeing red and hearing a whooshing noise, and the experience matched most descriptions I've read. It frightened me though, and I sat up immediately, which is something I really regret doing now because I've never gotten that close since.
The weird thing about it is that I remember sitting there for only about ten minutes before the vibrations and everything started happening, yet I've since made other attempts while sitting completely still in my bed for up to thirty minutes and getting nothing. I've made sure that I'm "sufficiently tired" (i.e. able to fall asleep if I want to), ignoring impulses (itches, readjusting myself, even refraining from swallowing if I can, though I'm not sure if that's necessary), and made sure that I'm not going to be interrupted. Nothing. I don't know what circumstances made that first experience happen so easily, but I sure gypped myself.