Ross Evans began thinking about all the stuff being precariously pedaled around in the Third World after a stint teaching ex-soldiers in Nicaragua how to be bike mechanics.

Yesterday at the Museum of American History, he and teammates from Stanford University showed off Evans's brainchild: a bike whose attached cargo system can smoothly transport hundreds of pounds.

Down the hall, a team from Rensselaer Polytechnic demonstrated the Double Dutch Jump Rope Machine with four mechanical arms moving two ropes in syncopated rhythm.

Tahira Reid thought of that one when she remembered how hard it was years ago to find rope swingers in the Bronx to help her practice for her junior high jump-roping team.

The XtraCycle and the Double Dutch were among dozens of inventions strutted by students. The exhibits were convincing proof that America's genius for invention lives on.

But the inventions were only a fraction of the challenge: Each team composed mostly of engineering students also had to learn the business of getting their products to market -- intellectual property protection, grant proposal writing, market research, patent law, manufacturing issues.

The projects were life-changing, said students who explained that it got them thinking about becoming entrepreneurs rather than employees.

That was precisely the hope of Jerome Lemelson when he created a nonprofit foundation to nurture a new generation of innovators and entrepreneurs.

Lemelson himself held 500 patents at the time of his death last year -- a record rivaled only by Thomas Edison. He invented the fax machine and the flexible track used by Hot Wheels cars and conceived the technology that made the VCR and the Sony Walkman possible.

Although Lemelson based his philanthropic endeavors at the Lemelson National Program at Hampshire College in Amherst, Mass., his foundation helps 60 colleges fund projects.

The students, at various stages of developing and marketing their products, all have big ideas.

The U.S. American Jump Rope Federation already seems interested in the Double Dutch machine, Reid said. Jump-roping is a worldwide market, especially popular in South Africa, she said. She envisions them in gyms everywhere, saying, "People are going to get tired of Stairmasters and rowing machines."

There are still kinks. As a child at the museum pointed out, the ropes weren't making perfect arcs. "It's a prototype; it's workable," answered Simone Thompson, Reid's teammate. They need to get the rope weight just right and tinker with the engine.

Although Evans set out to help the poor in the Third World, his market research has convinced him that the XtraCycle also could ease pollution in the United States, where 2 million people a day drive less than a mile to pick up groceries and such.

A team from Northwestern University has a patent pending and high hopes for its Surgical Dustbuster -- a cordless, hand-held blood-sucking machine. Surgeons needing to siphon off blood now use big machines that plug in the wall and sit on table tops. Kate Andrews hopes the machine will one day be used in operating rooms and in ambulances. She and her partner own 25 percent of the potential value of the device, and the college holds a 75 percent share.

A team from Hampshire College is making a final prototype of a solar hydrogen system that takes energy from solar panels and windmills, converts it into hydrogen and stores it in fuel cells. Currently, alternative energy is stored through a system of lead acid batteries. Carl Mas believes that the car industry's interest in fuel cells is about to create an exploding market.

The experience of a Massachusetts Institute of Technology team demonstrates how the projects get off the ground. In that case, a professor gave a vague assignment: create a marketable medical device that somehow utilizes the Internet.

The team started by researching medical procedures and discovered that 60 percent of all reconstructive surgery involves the knee and that patients need therapy thrice weekly for months.

Thus, the Kneehabilitator.

From the convenience of home, patients may one day use the Kneehabilitator to strengthen their legs and increase muscle firing activity. The patient gets instructions from the Internet, and information about the workout is sent by computer to the therapist. The therapist studies that data and creates the next day's exercise plan.

The project has ended Phil Frei's confusion about what to do with his life. "I've decided to start my own company," he said. "I'll have my hands in business and in engineering." CAPTION: Shawn Stern, of MIT, demonstrates the Kneehabilitator, which would allow someone to rehabilitate from surgery at home through use of a computer.