What is the purpose of a prayer box on your dorm room door?

Last semester, on my floor, one prayer box popped up, followed by another a couple doors down. Each has paper and a pen next to it.

I understand at a church, or even the religious building(s) on campus. I also understand putting prayers or bible verses on your door.

But why ask other people to write prayers and put their names on them and give them to you, a layperson? What is going on here?

If no one knows, how do I ask tactfully?
I doubt it’s for a class – no class lasts both semesters. And this week, one of the girls put up a notice saying that if you took her pen or paper, you’d be struck by lightning, as God was watching.

I’m not in college, and I didn’t do this while in college, but I have often asked people if they have any names for the prayer roll. Perhaps this is a way these people are doing that. I am a layperson, but what I do, is take the names to the "official" prayer roll and put them on it. Then I tell the person that I have done so.
Or perhaps, in a completely different vein of looking at this. Perhaps the persons who did this were doing it as part of a class assignment for a religion class.

EDIT: Maybe they are just going through a particularly religious phase. I did when I was in college, as did one of my next door neighbors in the last dorm I was in. I actually changed religions in college.

Perhaps you could ask one of them. Maybe something like, "I saw your box last semester and meant to ask, What’s it for? I mean, I know it’s for prayers, but is it part of your religious practice?" Once she explains, then you might say something like, "Oh, ok. Well I was just wondering. I might use it one day." Or if she seems to want to take it further than you are comfortable with (perhaps you’re not as religious as she is) then you might say something like, "I’m pretty happy where I am right now, but if I change my mind, or something, I’m glad you’re available as a resource."