[pen] Have you noticed how coffee expands when freed from the constaints of a cup/mug? One knocked over mug of coffee can flood an entire desk, soak into reams of paperwork and fill a couple of drawers.
And remember that if you do spill coffee on your desk: save the phone and the papers before worrying about the keyboard (keyboard £20, phone £200 if it's a clever one, papers probably several hours of your time).
I think job bags exist to protect their hated contents from coffee. The papers within are only soggy along one edge. The coffee in my keyboard was soaked up by all the crumbs already in there. My phone was protected by a layer of papers. In other news, I was taken out for lunch today by my boss. And no, I'm not about to lose my job :o)