I didn't write this, I found it while surfing.
I'm sure most people are familiar with what a drinking game is. So I'll just explain it briefly. While watching Sailor Moon, you take a sip of your favorite beverage (prune juice anyone?). This is geared towards the NA/DiC version, as I've yet to see any other version. (Not for long, though)
If the preview gives away the ending or the plot twist to the episode, take 1 sip.
Everytime the opening sequence has Star Wars-esque words flying into space, take 2 sips.
Everytime the title contains the word 'Blues', take one sip.
Every episode where a new scout is revealed, take 2 sips when the symbol appears on their forehead.
Every time someone asks, "Who're you?", take one sip. Take two if it's Darien asking. Take another sip if the person answers. Take two more if they follow it with a cheesy speech.
Every time Sailor Moon transforms, take 1 sip.
Every time another Scout transforms, take 2 sips.
Every time more than one Scout transforms at once and they blend them all together, take 3 sips.
Every time you see Darien transform into Tuxedo Mask, take 5 sips.
Every time someone transforms back, take 10 sips.
Every time someone shouts, "That's Rini's energy!", take 2 sips.
Every time Luna says, "I wish you'd take your own advice, Serena." or something to that effect, take 1 sip. Take 2 sips if it's not during the "Sailor Moon Says" segment.
Every time Luna or Artemis is physically abused in some way. This includes knocking them off people's shoulders, muzzling them, and squashing them. Take 1 sip. Take 3 sips if it's not Serena doing it.
Every time Luna says her password to Central Control, take 1 sip.
Every time someone says, "Oh, he's so dreamy.", take half a sip. If it's Amy or Molly saying it, you can take a full sip. If a guy says, "Oh, she's so dreamy" or a variant, you can take 2 sips. (Note: She's so ditzy, doesn't count as a variant.)
Every time Lita says someone looks like her old boyfriend, take 1 sip.
Every time everyone else says it before she gets a chance, take 2 sips.
Every time the monster has an affinity for repeating its name, take 1 sip. If it says it while it's dying, take 2 sips.
Whenever Alan plays his flute music, take 1 sip. If it's not the repetitive song, take 3 sips.
Whenever Ann says, "Alannnnn.", take 1 sip. If one or more of the people you're watching with repeats it or says it with her, take 2 sips.
Whenever Darien is accosted on the street by Serena, Ann, or any other female, take 1 sip. Take 2 sips if Serena's whining by the end of the encounter.
Everytime there's a flashback, take 1 sip. If it doesn't involve the Moon Kingdom, take 2 sips. If it features a cute kid Darien, take 3 sips.
Everytime a song from the English cd plays, take 1 sip. This includes the opening sequence. If the words are different, take 2 sips. If someone watching with you sings most or all of the song, take 4 sips. Take 5 sips if they start dancing or acting it out. (Note: Be careful of snorting your beverage through your nose if this occurs.)
Everytime Darien calls Serena, "Meatball head.", take 1 sip. Take 2 sips if anyone else calls her that. Take 3 sips if Darien calls her something different.
Take 1 sip if Serena is called a crybaby.
Whenever Melvin tries to ask Serena out, take 1 sip. If he asks Molly, take 2 sips. If Molly accepts, take 3 sips.
For every Melvin reference to the internet, take 1 sip. Take 2 if it's someone else. Take 3 if that someone else isn't Amy.
Everytime the word prune shows up, take 1 sip.
Everytime Serena attacks food, take 1 sip. If she sprays what looks like rice everywhere, take 2 sips.
Every time someone refers to Zoisite as female, take 1 sip. If he's called Madame Zoisite, take 2 sips. If anything hilarious happens in reference to Zoisite's gender, take 5 sips.
Everytime a monster dies, take 1 sip. If the monster is healed with Moon Healing Activation, take 2 sips.
Everytime a lead bad guy dies, take 3 sips. Then pause for a period of mourning.
Everytime a bad guy is turned good, take 2 sips.
Everytime a Scout is sucked into a vortex, take 1 sip. If it's Luna or Artemis, take 2 sips.
Everytime Serena turns into Princess Serena, take 1 sip.
Everytime Queen Serenity appears, take 1 sip.
Everytime we see Prince Darien, take 1 sip. If it's evil Prince Darien, take 2.
Take 5 sips if evil Prince Darien says he's never heard the name Darien before.
If you're really brave (and I mean brave), take 1 sip everytime Princess Serena doesn't make a contraction. (Make sure to have an extra six-pack handy)
Everytime a Scout gets a new transformation or power, take 1 sip. Take 2 if it's really cool.
If someone in your group shouts, "Make her go through the floor again!", take 10 sips.
Every time the Negaverse saps energy from a group of people, take 1 sip. If Molly's there, take 2 sips. If Melvin's there, take 3 sips. If Miss Haruna is there, take 4 sips. If a Scout is there and actually drained, take 5 sips.
Every time the bad guys decide to sap children or babies, take 2 sips.
Every time Raye's Grandfather's Temple is the site for the latest Negaverse invasion, take 2 sips.
Every time it's a school, take 3 sips.
Every time it's a charm shop or ice cream store, take 3 sips.
Every time Artemis makes a funny wisecrack, take 1 sip.
Every time someone attempts to sing, take 1 sip. If they're actually any good, take 2 sips.
Every time sparks fly, literally, between Raye and Serena, take 1 sip. Take 2 if it also involves tongues. Woowoo!
If you think you can spot a Scout who doesn't appear until later, take 1 sip. Take 2 if you can prove you're actually right.
If you pause the tape anywhere within an episode for reasons of scrutinizing it or rewatching something, rather than taking a snack break, take 2 sips. Take 5 if you do this so often the others in your group yell at you for it. Take 10 if you do this so that the episode lasts nearly 2 hours or more and no one complains.
If there's no Sailor Moon Says at the end, take 2 sips.
If you're watching a Japanese episode, take 2 sips. Take 3 sips if it's not dubbed, take 4 sips if it's not subbed. Take 5 sips if you're watching it without any English help at all and you don't know Japanese.
Take 5 sips if you can sing along with the Japanese theme and you don't know Japanese.
Day of Destiny:
Every time a Scout dies, take 1 sip.
When Darien dies, take 3 sips.
Every time someone says they're with Sailor Moon/Serena, take 1 sip.
Every transformation of Serena to Sailor Moon or to Princess Serenity or back, gets 2 sips.
When Queen Beryl finally bites it, take 10 sips.
If someone in your group cries at any point in the episode, take 3 sips. Don't take any if they're crying at Queen Beryl's death. Some fan they are! Hmph!