same thing happened to me the other day. if you still have the piece that broke off or any small, round, glass pieces of anything you could always stick that in the bowl first to block off so much airflow, then just put a screen on top of it so everything doesn't get fucked up.
i did this a couple of days ago and my pipe smokes fine again. if this doesn't work, macgyver that shit man, you're a stoner!
peace,
doc:rastasmoke: