Actors must be well known, if not for the role in a movie, then for another role in another movie or television show. (Kevin Bacon's appearance in Animal House is brief, but it does count.)
Any challenges will be settled by IMDB.com, or an agreed upon paper source if the internet is not availble, such as Video Hound. If those do not exist, majority rule will suffice. The victor gains a point (either for using an obscure role, or for challenging the error). One point is subtracted from the loser.
In the course of each game, a player may use a wild card. The player can link via a non-actor such as Director (Terry Gilliam), Composer (John Williams) or writer (Harlan Ellison). The next player can nullify that link by using an actor, thus gaining a point.
Players can link back to a player already used, but cannot use the movies already linked to the actor. (If V for Vendetta and Star Wars I were already used to link to Natalie Portman, they cannot be used if one links back to her later.) Also, if an actor costars with an actor in two or more movies in a series, a player cannot use any other movies in that series as a link. (Brent Spiner and Patrick Stewart can be linked via any of their Star Trek movies, but only once.)
Now, back to my link... Robinson on one end, Portman or Smith on the other... Smith links to Men In Black to Rip Torn to The Man Who Fell to Earth to David Bowie to Labyrinth to Jennifer Connelly to Hulk to Eric Bana to Star Trek (nexus) to Rachel Nichols to GI Joe (nexus) to Ray Park (nexus) to Star Wars I (nexus) to Samuel Jackson to Unbreakable to Fifth Element to Bruce Willis to Gary Oldman to Batman Begins to Liam Neeson (nexus) (Star Wars I = shortcut) to Natalie Portman (SW I) to Dustin Hoffman to Hook (nexus) to Robin Williams (nexus) to Jumanji to Kirsten Dunst (nexus) to Interview With a Vampire (nexus) to Tom Cruise to Legend to Tom Curry to Annie (dead ends with Peters, Finney, Burnett?) or Rocky Horror to Susan Sarandon to...?