I've remembered a few more - to start some creative renaming of Operations:
Operation Just Cause: I've heard it referred to as Operation Just Because more than once.
Operation Purple Dragon: This used to be an annual joint exercise at Fort Bragg. In the name purple referred to the jointness of the exercise and dragon can from the 18th Airborne Corps patch featuring a dragon (incidentally called the Gaggin' Dragon by some). The exercise planners should have been more creative as it became known unofficially as Operation Barney.
due to a deliberate policy of choosing random words out of a dictionary for op names (to avoid political overtones), most of our ops have obscure words for titles that don't lend themselves to nicknames. exercises follow a pattern of using a specific word associated with the unit, normally related to unit badge or traditional nickname (for example 1 div used "rhino", 3 div used "iron" etc).
Here are a few. in compliance to UK policy, op and exercise names are shown in all caps to distinguish them
op TELIC (the deployment to Iraq): as it was planned over Christmas 2002, it was apparently nicknamed
Tell
Everyone
Leave
Is
Cancelled.
Op BARRAS. A hostage rescue mission in Sierra Leone, after a patrol of the Royal Irish managed to let themselves get captured. The SAS and paras tasked with actually carrying out the mission felt in was suicide, and called in "operation CERTIAN DEATH"
exercise FLYING FALCON: in planning, a very normal signals exercise, but its execution was so botched by multipled, repeated mistakes that it rapidly became known as FLYING ▮▮▮▮▮▮UP.
units:
3rd Royal Tank Regiment: the Armoured Farmers (unit recruited mainly form the West country, a proverbially rural area)
the Royal Green Jackets (and other light infantry regiments, like the Rifles): the Black Mafia ("black" form the use of matt black buttons on uniforms instead of the shiny brass ones everyone else had, "Mafia" form the way the RGJ seemed to have an
exceptionally high number of senior generals come form it)
London Scottish: the Cockney Jocks ("cockney" and "jock" are standard nicknames for Londoners and Scottish, respectively.)
Cavalry regiments, in general: The Donkey Wallopers
Duke of Wellingtons: the Duke of Boots
9th/12th Lances: the Three Quarter Prancers (formed by an amalgamation of 9th and 12th lancers, hence the title. standing joke was that NATO standards meant they would need to change their name to decimal, ie the 0.75 lancers)