Children of different ages, shapes, colors and sizes huddle together in a warm cabin to pose for a picture on a cold winter's day.

These children, although perfect strangers the week before, resemble a large family. Among this sea of smiles is former tennis pro Andrea Jaeger, whose Silver Lining Foundation is responsible for these smiles.

A nonprofit organization, the Silver Lining Foundation helps children with cancer and other life-threatening illnesses by flying them to Aspen, Colo., to spend time with Jaeger.

"It's a magical world for children with cancer, where they can live out fantasies and enrich their lives, and have a lot of fun and laughter with kids going through similar situations," Jaeger said in a recent telephone interview.

The former tennis pro established the foundation after a bad shoulder injury. She had gone pro at age 14 and worked her way to No. 2 in the world. While traveling, Jaeger visited many children in the cancer units of hospitals.

Everything seemed to be falling into place for Jaeger -- everything except her shoulder. An injury forced her to end her tennis career abruptly at 19. But while her career was over, her love of children continued, and she established the Silver Lining Foundation in 1990.

"When I started the foundation, I asked myself if I could do this for the rest of my life because I didn't want to start something that benefits children and then have to take it away," she said.

While Jaeger appreciates the research being done to help cancer patients, she wants to make children's lives better in the present.

"There's a lot of people out there who work toward finding a cure for cancer. A lot of times it takes a year or a decade or a really long time to make the disease go away forever, and I wanted to help the children that are alive while I am alive, and I wanted to significantly change their lives instead of waiting 10 years from now."

Children with life-threatening illnesses between the ages of 7 and 18 are eligible for the all-expenses-paid weeklong trips to the ranch, which has a medical staff. Hospitals recommend children to the foundation, and parents and doctors must approve the visits.

During the foundation's early years, visits were held in an Aspen hotel. Today, five-day sessions are held throughout the summer and winter, housing up to 20 children per session.

In 1999, Jaeger and some supportive friends helped the foundation create an official home -- a big one. Situated on 10 acres in the Rocky Mountains, the 11-bedroom Silver Lining Ranch house covers 18,000 square feet. It cost $6 million.

"Now the kids have a permanent place instead of just being in a hotel when they come out to visit," Jaeger said.

The ranch is officially called The Benedict-Forstmann Silver Lining Ranch, for Fritz and Fabi Benedict, who donated the land, and Ted Forstmann, whose $1.7 million donation kicked off ranch development. Other sponsors include tennis players John McEnroe, Pete Sampras, and Andre Agassi and actor Paul Newman.

Friends show support in other ways, too.

"Sometimes my friends come by and say hello, like Cindy Crawford or Billy Goldberg or Paul Newman, so you never quite know who might appear on a given day," she said.

The ranch has allowed Jaeger to get the kids even more active. The children have the opportunity to get involved in horseback riding, whitewater rafting, tennis, fishing, arts and crafts, swimming, talent shows, sledding and skiing, depending on the season. The ranch also has a hot tub, outdoor pool, stage, library, darkroom, computer room and astronomy system.

Jaeger has fulfilled hundreds of children's dreams in her years with the foundation.

"I know one boy who was in a hospital for many months at a time and when he came out, he had never seen snow before. So he saw snow and then we took him skiing, and then he met a friend of mine, Cindy Crawford, who is a famous model. And he had a really great time."

Jaeger feels that keeping the kids active and involved can boost their self-esteem and improve their health.

"Laughter is always considered the best medicine. Those kinds of things are essential for us to provide for these families, so they know they have a support system, and the kids know that they can come out.

"A lot of times they come out and their self-esteem and their confidence and their ability and their motor skills increase dramatically just from going through a week of programs, and that's real important to us," she added.

Jaeger's foundation, which has touched more than 3,000 children so far, embraces more with every week.

"The whole meaning behind Silver Lining is that there's a silver lining behind every cloud, so no matter how horrible things are -- which, when you're a child dealing with cancer, can be pretty bad -- there is perhaps hope and a chance out there for you to have a better day and have some fun," Jaeger said.

For more information on the Silver Lining Foundation, call (970) 925-9540 or see its Web site at www.silverliningfoundation.org.

ASSISTANT EDITORS: Katie Glass, 14; Kate Lumpkin, 14. REPORTER: George Jernigan, 12.