We all love books. But do you have any books that once belonged to other family members? If so, these can be a valuable home source.
I have a textbook that was my grandmothers when she was in 6th grade and then a book that was hers as an adult. It's nice to have a copy of her signature (she wrote her name in both books.) But what is also nice is that she didn't always go by the same surname as a child (her mother divorced and remarried) and so I have at least one item where I know what surname she was using during what time period.
And what about those "bookmarks" that may have been placed in a book. Yesterday, while looking through a book from my parents, a postcard from Reader's Digest fell out announcing a gift to them by my great grandmother. Now, this isn't earth shattering but, if I didn't know the information, I now have a postcard with my parent's names and old address as well as my great grandmother's name. This would also be important if I didn't know about when my great-grandmother passed away. I would know from the postcard at least when she was still alive. People use all kinds of things for bookmarks, photos, correspondence, documents, etc...
So checkout your bookshelf and the bookshelf of family members. There just might be some great genealogy finds hidden in the books.