A useless, futile, or foolish activity. A waste of time directed by higher authority.
I just learned this from a friend of mine who is in the military. I have never heard of this before, and think it's funny. He is in the National Guard, and was in Iraq last year for a while. I'm glad he's not there now. He told me he was pretty nervous when he was there. I think I would be a mess.
I found that definition, and a whole alphabitized page of other military definitions at: http://www.answers.com/Military%20slang.