In The Hitchhiker's Guide to the Galaxy by Douglas Adams, the answer to life is "Forty-two." However, we haven't figured out the question.
Except that I think the answer is actually explained by this clip from A Walk To Remember. Watch minute 4 onward.
Langdon: Forty-two, what do you mean, forty-two?
Jamie: Forty-two is befriend somebody you don’t like.
Langdon: [shakes head]
Jamie: It’s a- a to-do list I have, except for my life.
Langdon: What, like getting a new personality?
Jamie: Spend a year in the Peace Corps, make a medical discovery-
Langdon: That’s ambitious.
Jamie: Be in two places at once, get a tattoo-
Langdon: What’s number one?
Jamie: I’d tell you, but- then I’d have to kill you.
The answer to life being forty-two is to live life wisely, just as Jamie does. To make to-do lists for your life, figure out what you want and go for it, and especially to try to befriend the people you don't originally like. There are such surprises in store. *smile* Forty-two means to live life in an intentional fashion.