Tim and Julie Rivenbark had a house, two kids and jobs they loved. But the Howard County couple also had a yearning for more experiences and fewer things.

"We were doing what we thought was the American dream," says Tim Rivenbark.

It took a couple of years for the sensible, responsible Rivenbarks to throw caution to the wind and make the decision to leave behind the familiar and embark on an adventurous yearlong quest to see the world.

Over the past several weeks, the couple sold their house and cars. They put their possessions in storage. Julie Rivenbark, 39, quit her job as a physician's assistant. Her husband, 43, convinced his bosses at Analytical Graphics, where he is director of North American sales, to give him an unpaid year off.

On June 29, the couple and their children, Tyler, 11 and Kara, 9, will board a plane at John F. Kennedy International Airport in New York City for a flight to Rome, the first stop on their around-the-world journey.

Each will carry a single backpack, filled with lightweight, washable clothes, a few toiletries and computers for doing schoolwork and blogging. Julie Rivenbark will take her beloved cameras to document their journey.

The family has been planning the adventure for a year, though they have only booked hotels and flights through November. And even those plans can be changed.

They expect to visit 25 to 30 countries, traveling east in pursuit of "an endless summer," says Julie Rivenbark, as the family shares a couch in the Columbia home of her mother, Kathy Younkin, where they have been living since they sold their house.

The foursome will hike to the Everest Base Camp in Nepal, a 14-day Sherpa-guided journey that will take them 18,000 feet above sea level. They also plan to go on a safari, see penguins and dive in a shark cage, and to explore South Africa, Nepal, India, China, Australia and New Zealand, Singapore, Indonesia, Myanmar, Cambodia and Vietnam, among others.

Their blog, earthtrekkers.com, will chronicle their adventures. The family hopes to inspire others to fill their lives with experiences, not possessions.

"It's OK to do something that scares you," says Julie Rivenbark, who grew up in Howard County and met her husband at the University of Maryland at College Park. "Live your life to the fullest."

Kara remembers when she first heard about her parents' plan. As she describes it, she and Tyler were in the car, and "Mom said, 'Guys, I have an idea. We think we should go around the world for a year.'" Kara's reaction? "It was awesome." Both children are thrilled with this unexpected turn in their young lives, though they say they will miss their friends.

The Howard County Public Schools System has been helping the family prepare to home-school Tyler, who just finished fifth grade, and Kara, who completed fourth grade.

They got additional assignments from their parents. Both are learning Mandarin, and will translate for their parents in China. Tyler will create a video blog. Kara is bringing her soccer ball, and "will try to do pickup soccer games all over the world," says her father.

The two children also each chose places the family would go. Tyler decided on Italy, and Kara picked Australia and Africa.

Like many people, the Rivenbarks enjoy travel. But it's one thing to take a couple of vacations a year and quite another to forsake a comfortable suburban lifestyle for a nomadic existence. Tim and Julie Rivenbark thought about the plan for years before finally deciding they would do it.

The seed was planted about five years ago, when Julie Rivenbark came across the book "WorldTrek, a Family Odyssey" (Rainbow Books, 2007), about a Texas family of four that traveled around the world. She bought the book and read it.

"When I was done, I was like, 'It's not that crazy,' " she recalls. Her husband was intrigued as well.

They kept talking about it, growing more convinced over time that they would actually do it. They took Tyler and Kara on trips to Istanbul and Norway, and were pleased to discover their children were excellent travelers. A year ago, they "were ready to take that leap," says Tim Rivenbark.

The couple say they gained confidence for the journey from their experience training for and completing full triathlons —Tim Rivenbark completed one in Florida and one in New York; Julie Rivenbark finished one in Florida. After swimming 2.4 miles, biking 112 miles and running 26.2 miles, they knew they could handle the physical and mental challenges of their adventure.