The Fire Blanket. It's ubiquitous in terms of communal kitchens (even a few rental places I've seen have had them) yet I've never seen one in use.
They don't even make any appearances in classic Van Damme / Segal / Willis / Arnie / Stallone type action movies where there's a fight in a kitchen, or when someone has to make a dash into a burning building/room to rescue someone.
It's a shame. I want to see Bruce Willis whip some guy's face off with one in Die Hard 5.