My apartment mate and I have been working our way through TOS for the last few weeks. We made the episode selection a game of sorts. My friend will give me a stereotypical and common Star Trek related situation, theme of Character element. I then pick an episode that fits his request. Some of things he has suggested and the episode I have picked are as follows...

Shuttle Craft related = Metamorphosis

Mutiny = Turnabout Intruder

Spock uses a Vulcan Power to save the day = Is There no Truth in Beauty

Gee, what smooth floors your cave has = What Little Girls Are Made Of

That sort of thing. It's been an entertaining way to pick what episode to watch. I've personally done the chronological and production order more then a few times, and this has been a nice change from that.