VANCOUVER, British Columbia — Every four years, Americans tune in to check out Olympic curling — even if they don't quite understand what they're watching.

The quirky sport with the sweeping is back on the air starting Tuesday, when the men's and women's tournaments begin at the Vancouver Games. A curiosity in the U.S. but a pastime here in Canada, the event figures to draw some spirited crowds to its 5,600-seat arena in a quiet residential part of town.

"This place holds twice as many people as Turin did," said John Shuster of the U.S. team. "I'm venturing to say it'll probably be pretty full."

There are about a million curlers in Canada, where the game is nearly as popular as hockey.

The U.S. men won bronze at the 2006 Games in Turin and will try for another medal at the Vancouver Olympic Centre. Curling will be aired on MSNBC, CNBC and USA throughout the games, so viewers will have plenty of chances to get to know the sport again.

It's been a while since Turin, so here's a brief review: Two four-person teams face off in matches that are 10 ends (or innings) long. They take turns sliding 42-pound granite stones down a sheet of ice toward a set of scoring circles.

Points are scored based on how close the stones are to the center of the scoring area, called the button. Competitors sweep the ice in front of the stone while it's traveling to change its speed or direction to make it "curl."

It's like shuffleboard, but on ice, and the quality of the surface is always crucial. Switzerland's Ralph Stoeckli praised the ice after practicing Sunday.

"If it stays like that, it's going to be a great event," he said. "We can't blame the ice."

Curling medals were awarded in 1924, then not again until 1998.

By The Associated Press