I would like to add a few things to my previous post, sorry if I stray a bit from the op:
I actually tripped three times with the shaman. It was completely unintended, I didn’t go to Peru to gain insight or to have a wild ride. I had never heard of ayahuasca before, so my mindset wasn’t bent on this.
The first night nothing happened.
The second night was really wild: I cried, I puked quite a few times, I went through a bout of sheer terror from witch the shaman steered me away (I was surrounded by nasty pulsating globes that didn’t like me and it felt terrible). I was lucky to have a doctor tripping with me, so while the shaman “steered away the evil spirits”, the doctor helped my rational side by reassuring me that everything would be ok and that I wouldn’t stay like that for ever. At one point I vomited and experienced catharsis: I spit out all my negativity and felt very relieved. I went through my relationships with my family and all the people I love, and gained certain personal insights. This gave me a feeling of well being that lasted for months. After the catharsis I found “the whiteness” of which I wrote before.
The third night I wanted to focus on keeping calm and for some reason I thought that achieving this was related to not vomiting, probably because all hell broke loose the previous time right after I did that. I managed to keep it all in and stay relatively in control. I experienced time in much the same way that **jjimm **describes, and even felt that I could make time slower by slowing down my breathing rate. Go figure.
Another weird thing that happened is that at one point I spoke to them and felt like the words were bending into impossible sounds as they came out of my mouth, even though in my mind I was clearly talking in Spanish. The doctor swears it seemed like some kind of structured but incomprehensible language. I must have sounded like Linda Blair 
I’ve read many accounts of people who went through the exact same experiences (the pulsating globes, the catharthical vomiting of the stone, the feeling of oneness, talking gibberish and other stuff), although none of those that were with me were even remotely close to what I experienced. One guy -not of a very introspective nature, I assume- ran away thinking he was a wild beast and swore he almost jumped on a horse with the idea of biting it in the neck.
There’s a lot to be discussed about how I achieved this “awareness”. The shaman told me that his goal was to achieve it through meditation, and that he was capable of doing this sometimes after many years of practice. This would seem the perfect way to go, but is not feasible for all of us for many practical reasons. On the other hand, ayahuasca is not physically or pshycologically addictive as far as I know. I’ve read a few studies (no links, sorry) and the shaman also said as much. Ayahuasca is not considered by them to be a drug, but a medicine. A proper amazonian shaman will not sell you ayahuasca for your own use because it requires guidance and certain conditions for the ritual to be correct (he will sell you peyote though). It is not illegal all along the Amazon basin and was in use way before the Spaniards made their appearance around there. Also, it’s hardly a recreational drug. It’s pretty incapacitating and also very introspective, definitely not the thing even the most hardcore psychonaut would take to a rave party. It’s sometimes used by alternative psychiatrists in Brazil to treat recovering heroin addicts, apparently with pretty decent results. Also, pharmaceutical companies have been studying its components for use in psychiatric treatment and went so far as to try to patent the active principle. This ended with a lawsuit by Equatorian indians on the grounds that it was part of their lore and therefore not patentable. They won the lawsuit because of a form error in the patent application, not because of principle. Sorry if I don’t include any links, but I looked this up a few years ago and don’t keep records. But most of it seems to be true.
Being a Spaniard myself, I live in a culturally very catholic country that has a long tradition of catholic mystics. Quite a few of these mystics achieved contact with God (capital G this time) through different means of mortification and deprivation that seem to trigger responses very similar to those of someone under the influence of mind altering drugs. This seems to me a very painful way of getting high, and quite different from the meditation of a yoghi, a buddhist monk or my friend the shaman. And sort of a cheat, or a crutch, in the same way that drugs probably are. I find this very ironic and with enough relation to the op to justify this post.
So I’m ok with how I got to that state of awareness. As time goes by I tend to think of it as a trick of the senses, but I still wonder. Even so, it’s amazing to think that the mind can make you experience something like this, and you have to wonder why so many people have so very similar experiences. Wherever the truth lies, a lot remains to be discovered.
I’ll try to find the book lekatt posted. Also, this post is not intended as a rebuttal of any kind, more as a follow uo on my previous one. I’d love to keep reading anybody’s thoughts on the subject.