[Knockwurst]

As others have said, easily digestible American movies from 70s and 80s. Scorcese, Kubrik, French Connection, Chinatown, Godfather I & II.

Then you can hit them with Hitchcock -- a master who made many entertaining movies.

Also, Billy Wilder -- The Apartment, Some Like It Hot

Then you got the Noir Films -- Bogart and Cagney, Sunset Blvd., Double Indemnity (Wilder).

By then they've prolly got their fill of American, and you can go to the French New Wave -- Godard's Breathless, Truffaut, Renoir Rules of the Game (not really New Wave but one of my favorites).

Bunuel and Fellini

Hong Kong -- Wong Kar Wai, Woo's early films.

I'll stop now.