Well, this is a little strange to say the least. The United States Postal Service WILL begin delivery on Sundays. But, it's only going to be for the Amazon company.

The struggling USPS has partnered with one of the LARGEST mail delivery users in the country in order to help the USPS and customers alike.

For now, they're only giving things a shot in New York and Los Angeles. However, they're pretty sure it's going to work out and so they're discussing rolling things out to other cities by next year.

Amazon is also saying that only Amazon Prime members will be able to have post delivered to them Sunday. But, if things work out really well it could be extended to regular customers.

[Source]