Every month, a group of older adults goes to Washington's Sibley Memorial Hospital, but they don't see a doctor or get tests. They're not sick. They come just to laugh.

They gather in a room next to the hospital cafeteria for the "Laugh Cafe," one of the activities offered to seniors, including the 7,300 members of Sibley's Senior Association. The price of admission is one joke. "It's the best medicine," said Joanne Philleo, 79, of Bethesda, Md.

"I like to come with Joanne, and I love the jokes," said Jean Altimont, 89. "I never dreamed of telling a joke in front of a group, and the first time I came, I was real nervous."

The association for those 50 or older also offers other activities, including French and Italian conversation classes, day trips to museums, a current events group and tango lessons. In all, more than 10,000 seniors participate. "I call this a senior center without walls," said director Marti Bailey.

Sibley is one of several hospitals across the country offering social activities and other benefits to help seniors stay healthy and out of the hospital, while encouraging them to visit. Members pay a one-time $40 fee.

Some experts are concerned that the activities are less about health than about marketing to Medicare beneficiaries.

While hospitals may be seeking brand loyalty, they can also appeal to the increasing number of older adults who are looking beyond traditional senior centers. "Hospitals are trying to … change their image from places of sickness and death to ones of health and wellness," said Fredda Vladeck, director of the Aging in Place Initiative at the United Hospital Fund, a health research and philanthropic organization.

And the strategy may be working. "This isn't a hospital per se, because there's so many things to do," said Philleo."This is a place that contains a hospital."