I finally got to see Rachel Maddow fill in for Keith. The show itself wasn't all that great, with the exception of the BillO video(which totally cracked me up), but she did a good job.
It was like being able to take a deep breath and there actually being air in the room to breathe in. When Keith is on he has the tendency to suck it all out.
Maybe that's why he's gained so much weight.