ATLANTA — Wellwishers turned out Saturday to celebrate former President Jimmy Carter’s 99th birthday at his presidential library and museum.

Attendees saw video tributes from celebrities and competed in rounds of trivia that highlighted underappreciated details about his life and how much the world has changed since it began.

His actual birthday is Sunday. The Carter family planned to celebrate privately at their home in Plains, Ga., where he has been in hospice care since February, spending time his wife, Rosalynn, who is 96 and suffering from dementia, and other family members.