Neal Boortz mentioned a new phone scam on radio show today. This is a quote from an article in the Register:

The scam, which is known in Japanese as "wangiri" (one ring and cut), involves a computer using hundreds of phone lines to dial mobile phones numbers at random.

After one ring, the call hangs-up, which leaves the number stored in the receiving party’s mobile phone.

If the person returns the call they are connected to a sales tape soliciting business, and sometimes sex, services and are usually charged at premium rates for the call by the subscriber at the other end.

More info from google.