A couple years or so ago, I played an intelligent amulet (well, more of a scapular, really) in a short-lived forum-based D&D 3.5 game. This was a hugely ambitious and unwieldy campaign, with two DMs, way too many PCs, and the character requirement that we not only all start as strangers to each other, but that we each have at least three secrets that we'll try to hide from everyone else.
My character was a magic item created to be the tutor, guardian, and chaperone of some rich man's troublesome son while he attended college. Unfortunately, the amulet was stolen before it ever made it to the son, and was "activated" for the first time when the thief put it on. It promptly seized control of his body and decided to live its own life.
So my three secrets were as follows: (1) I was a freaking piece of jewelry, (2) I was a burglar (not just by riding the thief's body, but actually functioning as one willingly in order to support that body), and (3) even I didn't know who my host really was. Man, I wish that campaign lasted longer, but it was kind of doomed from the start, with a setup like that.