A familiar virus is re-circulating called the UPS, FedEx, or USPS Delivery Failure.
You will receive an e-mail from UPS, FedEx, or USPS along with a package number. It will say that they were unable to deliver a package sent to you on such-and-such a date.
It then asks you to print out the invoice copy attached. DON'T TRY TO PRINT THIS. IT LAUNCHES THE VIRUS!
Snopes article;
http://www.snopes.com/computer/virus/ups.aspIt never hurts to be aware of tricks to have you open potentially dangerous viruses. When in doubt just delete the e-mail.