The US Postal Service sent a cease and desist letter to the band The Postal Service for trademark infringement!

The Postal Service is an American electronic music band. They got their name because of the way they first started creating songs. Producer Jimmy Tamborello would write and perform instrumental tracks and then send them to vocalist Ben Gibbard. Ben would add his vocals and edit the tracks and then send them back to Tamborello via the US Postal Service.

Apparently, the USPS was not flattered by this nod to their service. In August 2003, they sent the band a cease and desist letter, citing their trademark on the phrase “postal service.” The USPS entered into negotiations with the band and decided they could use the trademark in exchange for promotional efforts and a performance at the USPS’s National Executive Conference. At one point, the USPS even sold the band’s CDs on their website.

(Source)