IF YOUR KIDS THINK their homework is tough, try this assignment on them. First, design and build a small, fully equipped contemporary home run entirely -- from the appliances and heating and cooling systems to the electric car parked outside -- by the sun. Next, ship your house across a state, a continent, even an ocean.

Its destination? The Mall, where it will arrive as one of 18 houses built by college students from as far away as Madrid and California and as close to home as the University of Maryland. Then, in one week, reassemble your house to full operating capacity and prepare to open your doors daily and welcome hundreds of visitors. Meanwhile, don't forget that for the next 10 days, the design, livability, efficiency, functionality and other features of the houses will be measured, evaluated and judged in 10 categories by panels of experts, until one house -- could it be yours? -- is declared the winner of the 2005 Solar Decathlon.

Ready now? Get out your pencils.

The Department of Energy-sponsored Solar Decathlon, which returns to the Mall this year after a successful inaugural competition in 2002, was created partly to help raise awareness of how we can make cleaner, more efficient energy choices without sacrificing the conveniences of contemporary life.

This weekend, the teams will arrive in the District with their houses to begin assembling a Solar Village. Although the village won't officially be open to the public until Oct. 7, during the week, you can visit the Mall and see the work in progress (though be aware that observers will be kept at a safe distance during the construction period). You also can follow building updates on the Solar Decathlon's Web site, www.solardecathlon.org, where you can also learn more about the competition and about solar technology, and view highlights from the 2002 event.

When students begin welcoming visitors for tours, the houses will be put through their paces daily in a wide range of energy-consuming activities, including heating and cooling, cooking, washing dishes and laundry, and running a home office. And then there are those electric cars. Each charged from its house's solar panels, they will be driven about on errands as part of the competition.

For many of the teams, the trip to the Mall has been a journey more than two years in the making, with plenty of classroom hours and nights, weekends, vacations and long days in the summer sun dedicated to the project. Now these students are eager to share what they've learned and show how they've applied it in their 500- to 800-square-foot houses.

For the students in your house, elementary schoolers and older, the Solar Village has much to offer, starting with its undeniable "cool" factor. Because they must be transported to Washington, the houses -- fitted with kitchen, bathroom, living, working and sleeping areas -- share the same compact charm that makes campers and treehouses so irresistible to the kid in all of us.

At the same time, any kid (or parent) who has ever ventured forth on the long and uncertain journey that begins with the words "some assembly required" is certain to appreciate the team members' tales of the trials, tribulations and triumphs involved when a group of students is tasked with making a high-tech house from scratch.

The Universidad Politecnica de Madrid's house, for example, was shipped across the Atlantic in eight containers; imagine trying to put that puzzle back together in only seven days. The University of Massachusetts at Dartmouth carried the challenge of the decathlon one step further; it is planning to donate its house to D.C. Habitat for Humanity after the competition, so everything in the house has to work not only for the judging, but in the real world.

Of course, the decathlon obviously offers a great opportunity for learning about the science and technology of energy. The village will include an "Anatomy of a House" exhibit "to show how individual energy efficiency and solar energy technologies work, individually and together," says Richard King, director of the Solar Decathlon and a team leader in the Department of Energy's photovoltaic research and development program. There also will be a number of interactive displays, an "Energy Today" area to educate visitors about American energy consumption and supply, and information about practical actions you and your family can take to reduce your own energy use -- good to know in these days of $3-a-gallon gasoline and skyrocketing heating oil and natural gas prices.

The main attraction in the Solar Village, though, will certainly be the houses themselves. Each one represents a unique idea of a home that is at once aesthetically appealing, energy efficient and comfortably livable.

Imagine residing in something like the futuristic Virginia Tech house, with its wing-shaped roof and translucent, insulating-gel-filled walls. Or how about a home that changes to suit your mood, like the Madrid university's "Magic Box," which features movable walls that allow the house to be divided into several configurations, including one with an interior courtyard? The U-Md. house, based on a design by student Luming Li, is raised above the ground, asking visitors to consider how we might literally change the way we live on the earth. If these ideas sound unlikely to be appearing anytime soon in a subdivision near you, other decathlon teams have chosen to give the future a more familiar face. Crowder College, in Missouri, whose 2002 decathlon entry took first place in three of the 10 events and won the People's Choice Award, this year brings an arts-and-crafts bungalow-style house to the Mall.

Inside, as well as outside, each house has features to interest students of all ages, such as the color-changing walls of the Virginia Tech house, the New York Institute of Technology's roof garden and the composting worm bin under the kitchen counter of the University of Colorado at Boulder's entry. Winner of the 2002 decathlon, Colorado returns this year with a new team and a new house packed with surprises, showcasing not only solar technology, but also a broad-based approach to building earth-friendly habitats, which it has detailed in handouts for the house's visitors. Built substantially from recycled and natural materials, the Colorado entry features a "menu" of ingredients, including wheat and soybean in the walls, bamboo utensils on the dining table, linseed-oil linoleum on the floor, the worm-composting bin made from hemp and paper-based fibers, and veggie-oil-based biodiesel fueling the truck that is bringing the house to Washington, trailing a faint scent of french fries all the way.

After all, what's inspiring about the Solar Decathlon is that students are asked not only to represent what could be possible but to show what is possible, right now, to demonstrate how easy it is to live comfortably using less energy.

"Most people don't want to sacrifice to live in a solar home," King says. So winning the decathlon requires more than whiz-bang and wonder. "These houses," King says, "have to look good, but they have to be buildable and practical. These are the houses that we hope today's kids will grow up to live in someday."

2005 SOLAR DECATHLON SOLAR VILLAGE -- Open to the public Oct. 7-16; weekdays 11 to 4, and weekends and Oct. 10 (Columbus Day) 9 to 6. The houses will be closed to visitors on Oct. 12 because of competition judging. For a schedule of events and workshops, information about the Solar Decathlon, team Web sites, photographs and daily updates during the competition, visit www.solardecathlon.org.

For more information and activities on solar and alternative energy and energy efficiency, visit "Dr. E's Energy Lab" from the U.S. Department of Energy at www.eere.energy.gov/kids.

Another interesting learning resource on solar power can be found at science.howstuffworks.com/solar-cell.htm.

Adults and children lined up to see Auburn University's Solar Decathlon house in 2002.

LED lights illuminate Virginia Tech's house, opening in Washington next week. Designers call it a functional celebration of solar technologies.