The Kennedy Center has been looking for ways to shore up its dance offerings ever since Michael Kaiser took over as director, and now, even as fundraising by arts organizations nationwide is suffering the effects of the stagnant economy, the Kennedy hopes that its patrons will help foot the bill. “In a letter this week, the center is asking patrons to join the Kennedy Center Ballet Circle by making contributions of $1,000 to $250,000. The money will support the annual season of ballet, and donors will receive ticket privileges as well as invitations to special receptions, rehearsals and discussions.”