In the history there are books that have influenced man's knowledge:
Charles Darwin's Origins of Species ...
Thoreau's Walden ....
and now ......
The Hitchhiker's 

Guide to the Galaxy
The Hitchhiker's Guide to the Galaxy is a five book trilogy (hint) is an intelligent blend of wacky humor in the British Tradition of Monty Python and thoughtful science fiction. It started as a BBC radio series, and evolved into the books, audio tapes, BBC TV series (with second series coming), a movie, and some of the greatest quotes and thoughts !
Great Links below.

Deep Thougth

THE AUTHOR - DOUGLAS NOEL ADAMS

BOOK - AUDIO - DVD LINKS Amazon - SF Site Review -

GAME LINKS

MOVIE LINKS Offical movie site - FilmFactory - IMDb - MTV -
Hollywood.com
- Touchtones movie Blog - Yahoo Movies -

42 Learn why 42 is the answer to life, the universe and everything

Deep Thought the ultimate 42 list -
Wikipedia - the Answer ti Life, the Universe, and Everything
BBC Guide on 42 - 42 Words, More or Less


Boxed items are from the movie site's Trivia Questions

Google Results
In Groundhog Day I counted the day repeated 42 times
Ghost
In You've Got Mail the Shop Around the Corner has 42 in the address
Level 42In Bringing Down the House, when Steve Martin goes Rapper, he is wearing jersey with 42 on it.
Finding Nemo
Martina McBride's This One's For The Girls verse for the girls about 42...
Matrix
Elvis died at 42 so did his fatherWindows Logo
They say there are 42 bridges on US1 to Key West FL and 42,000 people vist every year