Before I go back through the thread and read everyone's answers, I'll go ahead and post mine first.
I've always been deeply interested in hallucinogenics of any kind. The only thing that I have ever tried first-hand, was some mushrooms, but I'm pretty sure that I didn't eat enough of them, because all it did was slightly elevate my mood and made my limbs feel a little "loosy-goosy".
However, I'm more interested in "heavier" psychedelics in any case. Drugs like LSD, Salvia, and DMT fascinate me. I would love to try them someday, but I'm pretty terrified to do so. Plus, all the connections I have stick with pills, pot, and coke mostly, so I wouldn't be able to obtain it, even if I was brave enough to go through the experience.