If you want to make a fortune, you invent a computer game that features a couple of Italian guys with big mustaches running for their lives through the Mushroom World.
But if you're a tinkerer looking for a different kind of reward, you might invent a computer-driven pinball machine for quadriplegics.
Dan Goodman did that.
"Inventors are loved and thought of as bizarre," said Mr. Goodman, founder of the Silverthorn Group Inc. near Olney. "But it's important to apply your abilities to help other people as best you can."
Mr. Goodman's pinball machine -- with flippers that can be worked by breath if that's the only function a person has -- was one of 65 computer projects on display at the Johns Hopkins Applied Physics Lab in Howard County yesterday in a science fair devoted to aiding the disabled.
Called National Search, the juried fair pitted students and garage inventors against corporate and academic professionals in one of 10 competitions held simultaneously around the nation yesterday.
The winner was Kensington's Andrew Mitz, who devised a cheap learning machine that allows severely retarded people like his 5-year-old son, David, to develop thinking skills.
He won $1,000 and the privilege of competing for $10,000 in the finals at the Smithsonian Institute the first two days of February.
The invention of Mr. Mitz, a bio-medical engineer working on brain research at the National Institute of Mental Health, is called Wee Talk and uses a commercial computer chip someone else developed earlier this year.
Along with Wee Talk and Mr. Goodman's Arcade Access pinball machine, which placed sixth, were machines that let people make computer art with voice commands, machines that talk for people who can't, and a one-pound laptop computer for the blind that can recall data orally or print it out in Braille and standard English.
Like the gizmo Mr. Mitz built in his basement to help his son learn, many of the projects were born out of an inventor's frustration as a disabled friend or loved one struggled with simple tasks.
Mr. Goodman, a 31-year-old electrical engineer whose company makes its money in consulting, has been fascinated by pinball machines since he was 10 years old and his parents bought him a broken one in an antique shop.
The youngster repaired it, sold it, bought two more, repaired and sold them, and by age 14 had incorporated his own pinball repair company.
Years later, one of his pinball clients was a man in charge of a game room at the National Institute of Health, a man whose pinball-crazy teen-age son had been injured skiing and was paralyzed below the neck.
The man asked Mr. Goodman to put together a pinball machine his son could use. About a year later Mr. Goodman came up with Arcade Access, a commercial pinball game made by the Gottleib company and adapted for all manner of disabled people by Mr. Goodman's company.
The machine, which sells for about $7,600 and is still being refined six years after it was conceived, was intended to entertain the disabled. Along the way it has helped to rehabilitate some of them.
Mr. Goodman said one young man in Annapolis couldn't read after being injured in a car accident because his eyes wouldn't hold to a line of type. After playing hours and hours of pinball -- following the silver ball as it bangs and shoots its way across a contraption of noise and blinking lights -- he now reads.
And before he got his pinball machine, the young man's memory was so bad he couldn't remember the way back home after taking trips with family and friends.
Now he can.