First time around in the 1980's I recall being wheeled into theatre and seeing the machinery which immediately made me think of the monty python film and the "machine that goes ping" about which I made a joke.
The surgeon turned to the anesthetist and said "if she is going to crack terrible jokes like that you'd best put her out or we wont get any work done." The next thing I knew BAM it was like being hit with a sledge hammer.
I woke up hours later with no sense of time having passed, to find myself feeling deliciously clean, like I had been scrubbed for hours. I knew it was gone, and immediately I phoned a friend to tell them I was still alive. Later they told me that I sounded very drunk.
The second time round, last year, with the revision, it was like what Cait describes. Something was injected into my hand canula. The anesthetist said - it will go soft focus in a moment. I was talking, things went blurred, then they just faded out. I don't think I even finished my sentence.
I dreamed! I have never dreamed before under an anesthetic, but I had a lovely dream, and then I slowly faded back into reality still in the operating theatre, but with everything done and they looked at me and said, "That was a quick. Well perhaps we'd better take you back upstairs now." I asked what time it was and when they were going to get started, they laughed and told me it was about four o'clock which as I'd gone down at mid-day meant that at least 3 hours had passed. They meant that my coming round from the anesthetic had been quick. Apparently I woke up just minutes after the surgeon finished the last stitch and before they had even wheeled me into recovery.