I first saw the first version in a post by R. Knauerhase. This tale gives all indications of having been a feghoot at one time.

Imagine a land populated by sentient potatoes. It’s ruled by a benevolent monarch, whom the entire population loves. The King and his Queen have a daughter, Princess Idaho. One day, the king decides his daughter is old enough to marry, so that the monarchy will continue after he is gone. So, they schedule a Grand Ball, inviting the cream-of-the-crop of all the eligible young bachelor potatoes of the kingdom. From this auspicious group, the Princess should consider whom to wed.

The night of the ball, the Princess looks radiant. She makes small talk with the top potatoes from the best university. She dances with all the movie-star potatoes, and she spends time with all the prize-winning athlete potatoes.

After the party, the king and queen visit the princess’ bedroom. The king says, “Well, my dear, what do you think? You come from a fine line of potatoes. You’ve met the brightest, the handsomest, and the strongest potatoes the land has to offer. Who among them are you interested in marrying?”

She replies, “I don’t want to marry any of them. I want to marry Tom Brokaw.”

The queen gasps, but remains silent. The king turns russet red in the face. After a second to regain his composure, he tells the princess, “I forbid it! You cannot marry Tom Brokaw; he’s just a common-tater.”

Another version is considerably more shaggy. It goes:

Mr. and Mrs. Potato had three daughters who were as upstanding as they were lovely. One day the first daughter came home and announced, “I have an announcement to make.”

“And what might that be?” said Mother, seeing the obvious excitement in her eldest daughter’s eyes.

“Well,” replied the daughter, with a proud but sheepish grin, “I’m getting married!”

The other daughters squealed with surprise as Mother Potato exclaimed, “Married! That’s wonderful! And who are you marrying, Eldest daughter?”

“I’m marrying a Russet!”

“A Russet!” replied Mother Potato with pride. “Oh, a Russet is a fine tater, a fine tater indeed!”

As the family shared in the eldest daughter’s joy, the middle daughter spoke up. “Mother, I too, have an announcement.”

“And what might that be?” asked Mother Potato. Not knowing quite how to begin, the middle daughter paused, then said with conviction, “I, too, am getting married!”

“You, too!” Mother Potato said with joy. “That’s wonderful! Twice the good news in one evening! And who are you marrying, Middle Daughter?”

“I’m marrying an Idaho,” beamed the middle daughter. “An Idaho!” said Mother Potato with joy. “Oh, an Idaho is a fine tater, a fine tater indeed!” Once again, the room came alive with laughter and excited plans for the future, when the youngest Potato daughter interrupted.

“Mother? Mother Potato? Um, I, too, have an announcement to make.”

“Yes?” said Mother Potato with great anticipation.

“Well,” began the youngest Potato daughter with the same sheepish grin as her eldest sister before her, “I hope this doesn’t come as a shock to you, but I am getting married, as well!”

“Really?” said Mother Potato with sincere excitement. “All of my lovely daughters married! What wonderful news! And who, pray tell, are you marrying, Youngest Daughter?”

“I’m marrying Dan Rather!”

“DAN RATHER?!” Mother Potato scowled suddenly. “But he’s just a common tater!”