Mormonism, members of the Church of Jesus Christ of Latter-day Saints strongly believe in family history. Members volunteer in family history church buildings, categorizing and indexing tens of thousands of names a day, making it so that those who are curious about their ancestors can more easily find out their lineage. Members that do find their ancestors, and the ancestors weren't members, they do temple work for them.
Many non-members also do family history. Some do go to the church buildings to find out their ancestors. In fact, the First Presidency presented Barack Obama in 2009 with an account of his family history.
Doing family history can be exciting, as many members have said. They are interested in what their ancestors did in their time, where they lived, what they did for a living, and if they were related to anyone famous. Doing family history and work for the ancestors not only helps you fell good in the spirit, but it also gives you knowledge of what you did for those who passed on before you.