MANKATO — With the way they’ve behaved lately, you’d think Eric and Christie Nelson were in a rush to get the heck outa town.

Sold their house. Quit their jobs. Sold the pickup. Eric even got rid of his cell.

But there’s nothing mysterious or illegal going on. It’s just a couple of adventurers getting ready for their next big expedition.

The Nelsons, who are no strangers to seeing the world and have never been afraid of a little bit — or in this case a lotta bit — of hard work, leave this week for the bike ride of a lifetime.

After they depart Mankato, they’ll ride roughly 15,000 miles — through the U.S., Mexico, Central America and on down to Tierra del Fuego, the southern-most tip of South America.

Why?

“Why not,” Eric says, smiling the smile of a man who has cut all ties to local commitments and responsibilities and feels free.

It began about four years ago when Eric first dropped hints that he was thinking about going for an epic ride. Two years of persuasive rhetoric later and Christie was on board. Then they began the real planning.

A trip of this scale requires a certain amount of sacrifice. So Eric, an engineer at Dotson Inc. foundry, told his boss he was done. And Christie, a recently minted registered nurse, told her boss at Immanuel St. Joseph’s that she’d be leaving. They also put their house up for sale on Craigslist and it sold in two weeks. The pickup had to go, too. They tried to sell the Prius, but they ended up having to keep that.

They’ve tentatively scheduled a trip that will take them through 15 or so countries in 18 or so months. The “or so” part refers to their attitude. Part of this trip has to do with freedom from the American values of money and a rushed lifestyle — “to be able to let go and be a little vulnerable, depend on others ... We’re kind of addicted to the unknown,” Christie said.

They’re also known for living life to the fullest.

After college, the two joined the Peace Corps and spent two years teaching math, science and English in Vanuatu, a small, mostly impoverished nation.

“It was a tiny island,” Christie said. “No electricity, no roads, chickens running around.”

In Mankato, the couple, both age 31, make their way around town on two wheels instead of four. They were featured in a Free Press article a year ago based, in part, on an essay Christie wrote after she’d read an article in which people were bemoaning the high cost of gas.

“We forget most of our fellow human beings on this planet don’t even own cars,” her essay read. “Why do we think we deserve or are entitled to drive wherever, whenever and whatever we want, and then complain about the price? Move beyond society’s definition of how a proper person should travel.”

They are a couple who lives in the moment, a couple who believes that, if they don’t take this opportunity — or perhaps more accurately, create this opportunity — they’ll regret it.

Once they hit the Mexico border, they’ll get rid of their cell phones. After that they’ll keep friends and family up to date on their progress via a GPS system called “Spot” and by using the Internet. They’ll find cafes with wireless Internet and update their blog and speak with family and friends via Skype (an Internet application that allows users to make phone calls over the Internet).

“I suppose if we had an overall goal in this, it’s sort of letting the world impact us,” Eric said.

And when they’re done, in November or December in 2010, they’ll more than likely return to Mankato homeless and jobless and without a working cell phone. And they’ll probably be happy.