| A movie trailer comes on a little spool. It's an advertisement for a movie not-out-yet. The average trailer is about 11/2 thick on the spool. When the movie technician gets a new movie in, he unspools the main movie. Then, at the beginning of the film, he splices in the trailer. Multiple trailers are spliced. Then, after the movie the trailer is for begins begin shown, the technician will seperate the trailers from the film, and respool them. They then throw the trailers out.
I work at a movie theater, and now have a nice collection of trailers. They include:
Fight Club
Gladiator
One Night at McCools
Planet of the Apes
Final Fantasy
I'll splice them together one day...! cool | 
