By Robb Lewis | Fork on GitHub

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