Anyone want to know what the odds are that all the air molecules in the room you are sitting in will unexpectedly collect in a far corner of the room, leaving you to suffocate in your chair?

While I'm not disputing the fun to be had playing with astronomically large numbers, the actual odds of the air molecules staying there long enough for you to suffocate are zero. Air pressure is a statistical-mechanics phenomenon, and while in normal circumstances the mechanics is such that the statistics applies, in edge cases it isn't. In this instance, air molecules are constantly moving, and change direction only when they hit obstacles or other air molecules. Once they're all at one end of the room, there's literally nothing to stop them heading straight back again, just as if you'd opened a can of compressed air in a vacuum. There's no way that collisions alone can result in none of them having any velocity in the x-direction.

Peter