Yeah twice:
1. Took tramadol & effexor together, didn't know that was deadly. Coma for weeks, on life support, heart and breathing stopped numerous times, Glasgow coma score so low they saw little chance of me living. Had *intense* hallucinations, but that is apparantly a hallmark of serotonin syndrome. But some were utterly surreal like living out the final days of a Cambodian soldier from the 1970s in great detail, meeting an entity that was the personification of self-destruction, saying goodbye in spirit to each of my friends one by one with my best friends spirit telling me I had to go but not to be scared. I say 'spirits' but the experience was just like talking to them in person. Ie: Standing on a beach with my friend when he told me this.
About halfway through the experience and all these "visions" (I say visions but they were as real the time to me as the reality I'm experiencing now, including touch, sound, smells, etc) I began to realize that I must have died somehow (maybe the bus I was in crashed??) as I knew I was no longer in India (where this happened). At first I was really annoyed that I had died so young and that I had never found peace (I was pretty self-destructive), but as I was in the process of farewelling each of my friends (one by one, each in a different environment that sort of represented our connection to each other) the idea of being dead didn't seem all that bad (ie: I remember once I came out of the coma being really pissed off they had taken me away from that).
So yeah they flew me on a private jet with life support to a proper hospital where they managed to stabilize me with artificial respiration, certain drugs, etc., and made it so my heart didn't keep quitting. The doctor said to my parents when I was in the coma that I had been without oxygen to the brain for so long that even if I did survive I would be mentally retarded, but I went straight back to university and haven't noticed any cognitive differences compared to beforehand at all.
2. (This happened before the above) Flipping a car at ~100km/h with no seatbelt on. The irony is that if I had had a seatbelt on I would've been crushed to death and killed instantly, but instead I flew straight through the windscreen and then (I kid you not) the car had so much momentum that when it rolled I ended up back inside the car. Only my arm was crushed and nearly torn off, but apart from that just a few cuts and bruises

Nothing spiritual/mind-blowing happened during this event though, the only strange thing was that when I became conscious again (after being knocked out) inside the car-wreck I checked to feel if my limbs were OK, and at this time I hadn't seen that I had nearly lost my arm BUT I thought it was fine because when I tried moved it, it still had the full sensation that it was attached, so my brain was telling me I was moving it when actually I wasn't. Very bizarre feeling.
Some of the cumulative implications of these experiences I have now:
- You appreaciate life more.
- You don't overly fear death but you don't want to hasten it.
- Realize just how important deep connection to other humans is.
- Can't go back to a 'normal' way of life. You see it as far too valuable to be wasting in some job you don't like. The untrodden path of true self-discovery instead of flat-out materialism becomes the only real option, because you know full well it might all be over tommorrow. Even if you really wanted to you couldn't go back to that prior way of selfish/shallow thinking and goals.