I suggested several contests back "Alien Rituals", such as Swearing in the Kai, or Sheridan and Delenn eating the Flarn Lennier slaved over for days, or Spock's Wedding, etc.
We just had "Death by Villian" in the Dr. Who Forum, you could always do that and exempt Dr. Who
Or alternate roles, such as Michael Dorn playing Worf's ancestor, or Mirror universe, or even the Episode where Sisko is a SciFi writer named Benny, and all the Aliens were sans prosthetics (Was that one called Far Beyond the Stars
One Day I hope to be the Man my Cat thinks I am
Where are we going? And why are we in this Handbasket?