Episode:2x24
The Ultimate Computer

Jack's Rating:

The Enterprise is fitted for tests of an advanced computer containing the erratic brain patterns of its inventor, Dr. Richard Daystrom, and begins a real attack on other starships during what is supposed to be a war game.

Features:
Stardate: 4729.4
Air Date: 03/08/68
Director: John Meredyth Lucas

Episode:3x02
The Enterprise Incident

Jack's Rating:

Kirk and Spock are captured by the Romulans while on a secret mission to steal a new Romulan cloaking device.

Features: The Romulans
Stardate: 5027.3
Air Date: 12/20/68
Director: John Meredyth Lucas

Jack's Review
One of only two appearances by the Romulans in the original series, this is a terrific episode. Plenty of intrigue and action. I own a t-shirt that says Vulcan Death Grip on it that uses the screenshot too.

Episode:3x13
Elaan of Troyius

Jack's Rating:

The Enterprise must transport Elaan, the beautiful Dohlman of Elas, to an arranged marriage on the planet Troyius.

Features: The Klingons
Stardate: 4372.5
Air Date: 11/29/68
Director: John Meredyth Lucas