I'm listening to the podcast of the January 12, 1941 show right now and loving it. The plot is that show writers Eddie and Bill have failed to write any script for that week's show. Ed & Bill are (I assume) playing themselves--and darn well, too.
What makes it doubly funny to me is that after all the writers' lines, there's marked "extra" laughter that's so loud and distinct from the audience's that I have to think it's coming from all the regular show workers who-as always happens at these things, are slayed by the inside-joke aspect of the whole conceit. I find myself laughing as much at the laughter as at the writers' lines!
Funnily enough, for once Jack seems to keep his composure during his "PO'ed boss" end of the exchange and not fall apart himself. Of course, it's still just the start of the show, so there's time yet. What a gem. Makes me wish I could be in the writer's room with the bunch of them.