Today, a tale from the book known as Kohon setsuwa shū 古本説話集, or "Old book of legends" — this being a provisional title assigned to the medieval work when the only known copy of it was discovered in 1943 without a cover or any useful identifying information. The tale is called "The woodcutter" and also appears in the Uji shūi monogatari 宇治拾遺物語 under the title "The woodcutter's song."

いまはむかし、木こり、山もりによきをとられて、わびし、心うしと思ゐて、つらづえうちつきてをり。山もりみて、「さるべき事を申せ。とらせむ」といひければ、
  あしきだになきはわりなき世の中に
  よきをとられて我いかにせん
とよみたりければ、山もり、かへしせむと思ひて、「うゝ/\」とうめきけれど、えせざりけり。さて、よき、かへしとらせてければ、うれしとおもひけりとぞ。人は、たゞうたをかまへてよむべし、と見えたり。

Once upon a time, a woodcutter had his axe (yoki) taken from him by a mountain ranger. But the woodcutter looked so helpless and miserable sitting there with his chin in his hands that the ranger said, "All right, say something clever and I'll give the axe back." So the woodcutter recited a poem:
  Even a bad one is better than none -- you need one to make the cut in this world,
  So now that my good one is taken away, I axe you, just what shall I do?
The ranger wanted to reply in verse, but all he could do was groan "Ooh, ooh!" So he gave the axe back, and the woodcutter was most delighted. And so we see that people must always be ready to recite a poem.

I like this story for a few reasons:

1. The poem is great. There are two main puns going on: yoki "axe" vs yoki "good", and wari naki "senseless, hard-to-endure" vs wari naki "free of cuts" (e.g. like the trees the woodcutter can't cut without his axe). My rendering is groan-inducingly bad mainly as an excuse to use the "axe/ask" pun.
2. The ranger is not simply lost for words. He actually moans "うゝ/\" ("uu, uu" or maybe a stutter: "u- u- u- u-"). This isn't a pun or anything, it just makes me laugh.
3. The moral is not "don't be a jerk" or even "don't start beef if you can't finish it," but rather, "always be ready to freestyle eight bars."