Why are there military helicopters buzzing around Aurora Colorado?

I don't know if you've heard it, but over the past couple of weeks or so there have been more than a few very loud and very close aircraft flights over the part of Aurora CO. Has anyone else noticed an unusual amount of military aircraft flying over their area lately?|||Its a trainign exercise, the helicopers always fly low over Bragg when I am running on the firebrakes just to show off.