Two other scams:
1. this one has been done by Nigerians in Bangkok. Some guy will approach you and tell you about something very valuable he'll sell you for very little. He'll give it to you to look over. When you return it to him he'll claim that what you returned is not what he gave you and is in fact worthless. His big scary buddies will show up and ask for what he gave you and if you won't give it up, they want the equivalent in money or they'll mess you up. So never take anything from a stranger to check out.
2. the ATM scam. many variants. one is that your card gets stuck in the machine (due to something the bad guy put in the slot earlier). you stand there trying to get it out. A friendly person comes up and suggests that you try entering your pin again as that will usually fix it. You enter your pin while the bad guy watches. Of course this does nothing. You go off to report the problem. The bad guy pulls out your card (since he's knows it's being held by a u-shaped piece of plastic). With the card out now, and knowing your pin, he just puts the card back and steals your money.
so... never enter your pin with some stranger nearby... no matter how friendly he is. And in general cover your hand when entering your pin... there are other scams that involve card duplication but they all require your pin number.