Americans already have heartily embraced the extreme boxiness of Toyota’s Scion xB, and now two similar vehicles have joined the xB in the marketplace — the 2010 Kia Soul and Nissan Cube.

The Soul arrived first, going on sale in March, but the Cube is right on its heels.

While the two are quite different in their styling, the concept is the same: a small box on wheels, with lots of interior space, that doesn’t leave a big footprint (like one of those SUVs that people love to hate these days).

For this report, we tested the Soul, which one of my colleagues took one look at and declared it to be a “clown car.” He even started humming a circus song.

The Soul does have a clownish look about it, but that’s a huge part of its charm.

For one thing, the roofline is sloped down from front to rear, while the belt line rises to meet it. That gives it almost trapezoidal side windows.

The rounded nose with its large headlights adds to the car’s comical look, created by Kia’s Southern California design team. The vehicle is “aimed toward the young and young-at-heart,” Kia says. As with the xB, this car will appeal to a young crowd, for sure, but also will be embraced by lots of us who are much older. Prices begin at $13,300 (plus $695 freight) for the Soul base model with a 122-horsepower, 1.6-liter four-cylinder engine and five-speed manual gearbox.

No automatic transmission is offered with the base engine, though.

The other three Soul trim levels — Plus, Exclaim and Sport — come with a 142-horsepower, 2.0-liter four cylinder and a choice of the five-speed manual or a four-speed automatic.

Prices range as high as $18,900 for the Sport version with all available options.

Our tester was the Exclaim model with automatic transmission ($17,900 plus freight). It came in a funky color Kia calls “Alien green.” It looks like it just rolled in from Roswell, N.M., after departing from the Mother Ship.

Standard features on the base model include a chrome grille, auto-off headlights, solar glass, black door handles and side mirrors, air conditioning, tilt steering column, power door locks, power windows with driver’s side auto-down, external temperature display and digital clock in the radio, dual-level glove box, rear-window defroster, cargo area light, body-color front and rear fascias with black inserts, black side molding, rear wiper/washer, variable intermittent front wipers and 15-inch steel wheels.

Once inside, this car that seems so small on the outside is quite cavernous.

The front bucket seats were as comfortable as I’ve found in a car that sells for under $40,000, and the interior layout was designed with practicality and usefulness in mind.

Where with the Sky I never found a place to put my cell phone, the Soul had lots of cubbies and cup holders that were perfect for my assortment of traveling electronic companions, including my PDA phone, iPod Touch, classic 80-gigabyte iPod, backup phone and the ever-present pocket-size Sony digital camcorder (you never know when you might need that at a moment’s notice).2010 KIA SOUL

The package: Five-door, five-passenger, front-wheel-drive, four-cylinder, compact crossover-utility vehicle.

Advantages: Kia’s first entry into the boxy small crossover segment, this car has cool exterior styling, a roomy and functional interior, and a long list of standard amenities in four trim levels.

Negatives: No automatic transmission offered in the lower-price base model.

Engine: 1.6-liter or 2.0-liter four-cylinder.

Transmission: Five-speed manual or four-speed automatic (2.0-liter engine only).

Power/torque: 122 HP/115 foot-pounds (1.6-liter); 142 HP/137 foot-pounds (2.0-liter).

Length: 161.6 inches.

Curb weight: 2,560-2,820 pounds.

Brakes, front/rear: Disc/disc, anti-lock.

Side air bags: Front seat-mounted; side-curtain for both rows.

Electronic stability control: Standard.

Cargo volume: 19.3 cubic feet (behind 2nd seat).

Fuel capacity/type: 12.7 gallons/unleaded regular.EPA fuel economy: 26 mpg city/31 highway (1.6-liter); 24/30 (2.0-liter).

Major competitors: Honda Fit, Scion xB, Scion xD, Suzuki SX4 Crossover, Toyota Yaris five-door, Nissan Cube, Jeep Compass, Dodge Caliber, Chevrolet HHR.

Base price range: $13,300-$18,600 (plus $695 freight).

Price as tested: $18,595, including freight (Exclaim model with automatic).

On the Road rating: 8.7 (of a possible 10).