We have some great stairs where we do boot camp…any other “outside the box” exercises we can do on them?

I’m not sure these will qualify as “out of the box”, but here are a few suggestions (obviously you know your group better than I to determine appropriateness):

-continuous forward lunge step up (every step or every other step)
-continuous or static forward step up with hip extension and/or hamstring curl
-continuous forward run ups (skipping every two or three steps)
-continuous or static lateral single step up and/or shuffle
-continuous or static lateral single steps up with hip abduction and/or knee up
-forward bear crawl (not sure if this would be comfortable…)
-mountain climber
-tricep dip

Your knowledge and imagination will provide you with so many more!