Yep, this page is exactly what I meant by "cheat." I realized that with a comedy act it's better to tell than to show.
"the rule is really more 'show or tell'"
But I couldn't do that in this case. It had to be both. Even if you say that the scene as it is "doesn't work," the alternative is to skip from her clothes being torn away to the moment she walks off stage. I don't think I need to explain why this wouldn't work. You need to at least see a few scenes of her up there, get a sense of how the show went, what she talked about, and how it ended in order for the narrative to make sense.
"But after I've read some of Maytag's monologue - with samples ranging from the unfunny to the downright tragic"
Hmm, look I don't think I'm a great comedy writer either... but I honestly think you're exaggerating here. Think about it this way... if you were to take the monologue of any comedian, even someone as brilliant as George Carlin and write it down, a lot of the time it's not gonna seem very funny. I don't think you can emphatically say that her routine isn't funny based on what is written on the page... and furthermore, it's not like I've shown you her entire routine. In fact, you barely see any of it. You see the very beginning as she starts to go into it, and you see a short scene from the end. As that is the case, I don't think it's necessary for you to suspend any disbelief, as you don't have enough evidence to go on either way.