Episode:2x15
The Trouble With Tribbles

Jack's Rating:

When the Enterprise stops at the K-7 space station to pick up a shipment of a new type of grain, trader Cyrano Jones introduces the Enterprise crew to tribbles, cute furry creatures that multiply so rapidly that they almost fill the Enterprise to its seam

Features: The Klingons
Stardate: 4523.3
Air Date: 12/29/67
Director: Joseph Pevney

Jack's Review
Here we have one of the top 5 TOS episodes and easily one of the top Star Trek episodes ever made. It's funny as heck and probably one of the most accessible episodes of the original series - making it a great episode to show anyone you want to introduce to Trek.