Sir without knowing more about your specific situation, my observation would be that the mission has become routine and without challenge. Is it possible to begin cross training into other specialties in the same shop? Or even cross training in other collocated shops? A new intellectual demand may bring folks around by requiring them to be more involved and focused. Cross training is always a great career development tool as well.
You may also try an off duty team builder that is completely unrelated to everybody's primary duties.
Sir, no worries. My interpretation was that you were seeking some solid leadership advice for a difficult situation; nothing more or less. It has happened to us all at some point during our careers. Mind numbing is the military way...;-)
I would echo Major Apticar's comments. I cranked out my first master's degree as a diversion from the real world by taking a class or two at a time. It was a great personal morale booster for me, and a number of my subordinates got onboard with taking some college classes as well. Was a good thing altogether.
Has your situation improved? Has any changes been made to off duty activities or official duties? I worked Low Observables in the AF and had a lot of morale issues in the shop I was in. I can offer up a few suggestions but they may not apply in your situation.