Guest stars:

William Schallert       Nilz Barris, Federation Undersecratery of Agriculural Affairs in 'this' quadrant.

William Campbell        Capt.Koloth, Klingon ship captain (also played Trelane in "Squire of Gothos")

Stanley Adams           Cyrano Jones, wondering merchant and prospector
Whit Bissell            Mr Lurry, Manager of K7
Charlie Brill     Arne Darvin, Assistant to Barris
Ed Reiners              Admiral Fitzpatrick of Star Fleet Command
Guy Raymond             "Ed',Trader/Bartender on Space Station K7
Paul Bradley            Freeman (?)
David Ross              Guard
John Burke (not appeared) Chief Astronomer of the royal Academy in Old Britain who first mapped the area of Sherman's planet

Crew Appearences:
Kirk, Spock, McCoy
Uhura
Chekov
NO sulu
Scott

Story:
Tribbles, furry creatures which eat incessantly and multiply at warp speed, cause headaches for Kirk and company while on assignment to protect a grain shipment on Deep Space Station K-7. Here, they encounter the cuddly creatures who've begun munching their way through the grain while rapidly filling every nook and cranny of the starship. Adding to Kirk's woes are the troublesome trader and some nasty Klingons bent on sabotaging the grain shipment!

Factoids:
Sherman's planet, undeveloped, claimed by both the Feds and Klingons, nearest klingon outpost is only 1 parsec away (close enough to smell them)

the battle of Donnatu 5 was fought 23 years ago for control of  the area

Organian Peace Treaty terms are that each side must prove it can develope the planet most efficiently. (See Errand of Mercy)

code 1 emergency = disaster call = priority 1 disress call

quadrotriticale, a high yield grain, 4 lobed hybid, perrenial, the only earth grain that will grow on Sherman's planet.

Regulan Blood Worm= soft and shapeless

Denebian Slime Devil = unknown (but creates a certain mental picture)

Quotes"
"I have never questioned the orders or the intelligence of any representative of the Federation...until now."
_____________
"I was not aware, Mr. Spock, that 12 Klingons constitutes a swarm."
____________
I won't touch a hair on its head...where ever that is."
______________
"The most I can figure out is that they are born pregnant, which seems to be quite a time saver."
______________
Well, Cyrano Jones says that a Tribble is the only Love money CAN buy"
_____________
They can reproduce at will..and brother have they got a lot of will"
_____________
I gave them to the klingons.....where they'll be no "Tribble" at all."

And so many others its hard to not write the whole episode as a quote.

This one has got to be the favorite episode of just about everyone, because ... well, just because.