I've only had one that I can recall. I dreamt that I woke up, and started writing my previous dream in my dream journal. The entire process I was actually recalling the events of the previous dream and I assume I was writing them down in a lot of detail (I filled up about 4 pages, but I couldn't make out any words because it was very blurry). I woke up that morning and went to check my dream journal and read over what I had written... The shock I got when there was nothing there made me question whether I was still dreaming or not, lol.