I\'ve had this problem twice (both times on Sunday mornings, oddly enough, but it usually resolves in the afternoon).
The thing that worked for me was just to wait.

The terminal velocity of a penny is about 60.3 miles per hour (I think it was).  It does not have the force to break bone or usually even break the skin.  On Mythbusters (on the Discovery channel) they rigged up a staple gun to shoot pennies at terminal velocity.  They also shot eachother with it and only came out with a few bruises.
They also rigged a rifle or shotgun or some other form of firearm to shoot a penny at about the same speed as a bullet.  When shot at the same speed as a bullet, it had the same effect as a bullet and shattered the dummy head they were using to prove that a penny *cannot* fall off the Empire State Building and kill people at the bottom or wedge itself in the concrete unless somehow someone shot from the top with a gun.

Ok, now that I\'m done being a geek, I think it would be cool to have random little cave-ins or such.  After all, the game *does* take place in a cave, and anything with a roof could send debris down in some way.
As for what is falling, maybe some things of value such as gems and ores, but a greater number of just random bits of rock than stuff worth anything.  Also, though, the falling rocks would probably be concentrated mainly in one place, which would be the weakest part of the roof/cieling/whatever, and so most of the people would probably just get hit on the head with chunks somewhere between the size of a baseball and random pebbles (hopefully your char would be on the side away from all the huge rocks, that is).  Even then, stone forms in layers, so it\'d be likely that the parts falling would be long, flat, and rather skinny unless they were a stalagmite/stalagtite (I dunno which is which any more), making them probably just a few feet long and wide, and maybe up to one foot in height...  Or maybe I\'m just overthinking things, so I\'m just gonna shut up now.

Thankee  Yes, now I see the symmetry is a bit wonky...  I stopped fixing things after I wrinkled the paper severely right below where I cropped the picture and realized I was gonna end up killing the whole thing if I continued. ... And I still forgot the whiskers.

Which one of the Opencanvas Experiments?  There are three I believe.. Draeger Zolin, Cronus, and BlackDragon.

Yeah.. I\'ve sort of half given up trying to RP, at least until my RP-goon friends get PS working on their computers.

Coming from the wide world of forum RPing, I\'d find it nice if I could find someone who was actually IC.  I generally try to stay IC until I figure out if the other person is RPing or not, and act accordingly.  So far, I think the only person I\'ve come across that was IC was Monketh.

But yes, hopefully that\'ll change someday.  (Hm, maybe having something that you can toggle that tells people if you\'re IC or OOC at the moment would help with that?)