What do you get when you take five women who can all sing, dance and act, and dress them up in nuns’ habits? Sounds like the beginning of a joke. And, in fact, it is. Except, instead of these nuns walking into a bar, they are walking into a theater. StageDoor Theatre in Conifer, to be exact. And the joke is on us, because this is precisely the comedic combination that will leave audiences rolling in the aisle when “Nunsense” opens on Sept. 26.