Nigerian (and Not-So-Nigerian) Fund Transfer Scams
This particular scam has been circulating for years, but it has numerous permutations. Generally, the context of the message is that some prince or official or estate or fugitive in a foreign country wants to transfer a large sum of money to you for "safe-keeping," but in order to do so, they need your bank account information. DO NOT PROVIDE ANY INFORMATION. The intention of these scammers is to create euphoria in the recipient over the thought of receiving a ridiculously large share of the money for free. The scammer then overdraws money from the account the victim provides, leaving 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." It continues with more disjointed information about banks and transfers that actually doesn't make much sense. Either way, the message is fraudulent and should be immediately deleted.
Here is an example of the "FBI transfer" scam:
Here's another version of the fund transfer SCAM: