One finger
- Biff knocks on someone’s head and yells “Hello”
- Someone calls someone else a butthead (twice if it’s not Biff)
- People kiss
- Doc exclaims “Great Scott”
- Marty says something is “Heavy”
- A song from the soundtrack appears in the film
- Someone yells “Nooooo”
- Someone falls for an obvious joke or gag
- Someone says “future” or “paradox”
- Marty looks confused
- Someone ogles a woman
- Marty gets called a chicken
- Any time rape/sexual harassment is ignored by other people
Two fingers
- Marty uses a false name
- DeLorean malfunctions
- Someone/thing fades from exisitence
- Marty is pursued by a Tannen
- Lorraine acts seductive
- A song that’s not from the soundtrack appears in the film
- Marty displays his guitar playing prowess
- Townsfolk treat Marty like a freak
- A scene from a previous movie is replayed in another (three times if the actors differ from movie to movie)
- An animal is used in an experiment
- Someone or something foreshadows a future event
- Someone sees his/her past/future self
Down it
- Gratuitous use of special effects
- Doc goes into lengthy explanation about how someones actions have affected the space/time continuum
- Popular artist/director/producer has cameo role
- Someone’s actions change the future
- Jennifer is rendered unconcious
- Doc speaks techo-babble
- The phrase “Back to the Future” is used
- The DeLorean is refueled
- Someone other than Marty or Doc discovers the time machine