Adventure

How important is adventure to the human spirit? Do we need adventure? I've been thinking about childhood adventure, and about books like Tom Sawyer and Huck Finn. Is a childhood without adventure a stunted childhood?
What about adults? Our lives often seem so safe, so controlled, so dictated by necessities. Does this mean that we have traded in passion for security?
To me, adventure conjures up images of vitality, both of body and spirit. We are most alive when we are in the midst of adventure. I suppose I most readily associate adventure with surfing, whitewater kayaking, rafting, backpacking, and things of that nature. To me, this sort of adventure not only makes me feel alive, but it also makes me feel connected -- I feel like I intimately belong to this world in which I live. This feeling is paramount to the well-being of my soul.
So, how 'bout y'all? How do you define adventure? How important is it to the human experience?