Washington ? A capital rite of spring — the swarming of the Smithsonian Institution’s National Museum of American History by tourists — took on a new dimension Friday when scores of award-winning young inventors set up their works in the museum’s lobby.

Think science fair at a jammed shopping center. “March Madness for the Mind,” it’s called.

Among the attractions: a cheap all-terrain wheelchair made from mountain bike frames. A microwave-based system that makes finding land mines carefree. A computer cord that lights up when it’s squeezed, so you can finally sort through the mad tangle behind your desk.

Some of the inventions are as new as chicks. Others are in the patent- or investor-seeking stages. All were fueled with money from the Lemelson Foundation of Portland, Ore., which is rededicating a room in the newly renovated museum this weekend.

The youngest team — 10 juniors and seniors from Clarksburg (Md.) High School skipping their AP classes — stole the show with the light-up computer cord.

Alex Ivanov, 17, got the idea last fall after he pulled the wrong cord while he was fixing his mom’s computer. With $10,000 from Lemelson, Clarksburg’s InvenTeam discovered that lighting was the tough problem. LED and fiber optics failed. Finally, a thin glow wire sometimes used as decoration in clubs did the trick.

Only about $2,500 remains from the grant, Ivanov said. Most of the money went for tools and materials, he said. “About a grand went to pizza.”

The InvenTeam hopes to complete its patent application by May, and Ivanov’s already thinking about the perks.

“First you get the money, then the power, then you get the girls,” he said.