Lights! Cameras! Mathematics! Action!
Students often mention examples of mathematics being used (or misused) in movies or videos. In turn, you can further these interests by either following up on their discussions or by introducing new examples yourself.
A good resource is Sheldon Erickson's Movie Math Mania (2003), available from the AIMS Foundation (Activities Integrating Mathematics and Science). The book is explores the mathematices included in six "popular" movies: Cast Away, The Matrix, Cool Runnings, Hunt for Red October, , and October Sky.
The discussion of each movie identifies key segments of mathematics-use, and then presents student activities involving the mathematics. Examples specific to proportional reasoning involve students in making props for shrunken actors or using estimation skills to find a cast away. Another example include watching heroes ride elevator cables to understand the concepts of integers and rates...or either save a damaged submarine or find a lost rocket while studying functions. Though designed specifically for grades 6-9, I suggest that they would be of interest to high school stduents as well.
To help teachers, each unit (i.e. discussion of a movie) includes key questions, learning goals, connections to the NCTM Standards, materials needed, specific mathematics content being explored, background information relative to the movie itself, suggested teaching sequences, discussion questions, extension questions, and black-line masters of student materials. All of this for one low price!