Imagine your favorite book. You love that book so much that you want to celebrate the person who wrote it. That's what a Heinlein Centennial is all about. It's a big party to celebrate the life and work of a very famous writer named Robert A. Heinlein.
Robert A. Heinlein was a writer who wrote lots of books about science fiction and adventure. He was born a long time ago, in 1907, and he died in 1988. So, 100 years after he was born, people wanted to honor him with a big celebration.
At the Heinlein Centennial, people talked about his life and his books. They played games, sang songs, and ate special treats. They even had a costume contest where people dressed up like characters from his books!
The Heinlein Centennial was important because it reminded people about how great Robert A. Heinlein was. His books helped people imagine a world full of amazing creatures, trips to far-off planets, and new technologies. And even though he's not here anymore, his books keep inspiring new generations of readers to this day.