A SQUISHY IDEA: Diagnosed with leukemia at 11, Kelsey Bohman spent nearly a year at Denver's Children's Hospital. After a bone-marrow transplant, doctors measured her lung capacity with a spirometer, which has patients blow into a tube to push a ball up a column. In 2002, she had an epiphany: Make a marshmallow launcher that strengthens kids' lungs and lifts their spirits.

MARSHMALLOW WARS: From their Glenwood Springs, Colo., home, Bohman and mom Pat created a launcher made from a 12-inch acrylic tube. Selling them for $8.75 apiece at fairs and on a Web site (www.kelseyskids.org), they've raised $19,000 for the hospital and donated 3,000 launchers to kids undergoing bone-marrow transplants. Tommie McHugh, the hospital's child-life specialist, says the launchers "totally rockā€”they serve a medical purpose but help emotionally and socially." Jessica Mussetter, 13, broke up her boring hospital stay by starting "marshmallow wars" with the nurses. "It was fun," she says, "but after doing it, I'd try the spirometer and get the ball to the top." Bohman, cancer-free at 18, also hopes the launchers send a message: "When I was in the hospital, it felt so good when someone brought me anything they had made. I wanted to do that for other kids."

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