My host family calls me Pedro. This is fine with me, since that was what my host family in Ecuador called me. I even have friends in the US who call me Pedro. I'm used to answering to it. Its only an issue when someone from WorldTeach calls my house looking for Peter. The first time it happened, my host brother told the caller that nobody with that name lived at the house.
While Pedro is fine, the baby (well by now he's a toddler) has begun to call me another nickname, which while far more amusing is also much more confusing. He alternatively calls me either tio (uncle) or tia (aunt). This has only started in the past week and is quite odd. I was confused when he was standing outside my door at 7am yelling for tia (aunt). I had no idea he was calling for me.
The reason he calls me aunt at times is that he has not quite figured out the difference between aunt and uncle in Spanish. For a couple of months every time he sees my host brother, his uncle, he says, "Tia!" and everyone in the room goes, "Tio!" back at him. The last week or so he has seemed to have figured out the difference. Now I'd say half the time he says Tia and half Tio.
I also just added pictures to my picasa account for anyone who is interested. They are from Easter Week so they're pretty old, but still some of them came out pretty well.