Consul-at-Arms points out that the phrase "Stone Cold Professional Diplomats" would make a great name for an in-house State Department rock band. I agree.
Good instincts, CAA. I've checked and found out that some variation of that name is already being used by at least two groups (this one and this one) as well as in the title of a song by Queen (Stone Cold Crazy) that was later covered by Metallica.
Since I know there must be lots of FSO garage bands out there somewhere, here are a few suggestions for names no one has taken yet.
The Black Passports
Headbangin' Cookie Pushers
The Band Extraordinary and Plenipotentiary
Attachés of Funk
Foreign Policy Fever
Rage Against the Démarche
Dipnotes N' Roses
The Red Hot Vice Consuls
CD/DC [that stands for Corps Diplomatique from the District of Columbia]
D.C.M. [Diplomatic Corps Musicians]
Pea and Gee'd
Back-channel Blues Band
Smart Power and the Bilateral Experience
The Foggy Bottom Boys [for a Bluegrass group]
and my favorite,
25 Percent Differential