I just read this on a fellow blogger's blog This Casita about the following scam:
"Apparently kids are calling in the wee hours saying they are someone in your family (i.e. nephew, niece, grandson, etc.) and then walking you through a sob story. Then, a couple of weeks later, they will call again and ask you to send them money because they are in trouble." She said that at about 3 am, her mom answered the phone to hear a young man whispering. "Hello?," she said. "This is your nephew," he whispered. When her mom said his name, he said yes, and then proceeded to tell her about how depressed he was. How he had relationship problems. So on and so forth - the entire time is a very muted voice."
For the full story, read her post here about it.