Nigerian (and other) Fund Transfer Scams
This scam has been circulating for years, but it has numerous versions. The context of the message is that some prince, official, estate, or fugitive in a foreign country wants to transfer a large sum of money to you for "safe-keeping," but they need your bank account to do so. The scammer plans to overdraw the account and leave the victim liable.
An interesting variation of this scam is a message purported to be from the FBI. It states that the recipient is in the midst of a funds transfer and warns that the recipient should only deal with Western Union, as all others are "Nigerian scammers." What? No way! DELETE them all!
Here is an example of the "FBI transfer" scam:
Here's another version of the fund transfer scam (click to enlarge):