OUSFG has a large library of SF and fantasy books, and a few other things that we've collected over the years. You can borrow as many as you like, if a fully paid up member of the society, and return them whenever you're in the mood. You can also sit in the librarian's room, browse for your favourite authors, and read the books there, until he or she decides to go to sleep and/or asks you to leave, or simply hunt through them for the occasional comments left by past OUSFG members on the blank pages at the end left delightfully free for such witterings.
The OUSFG library catalogue lists all the books that were previously in the library and both sets of stacks. We are currently (2013) in the process of recataloguing and selecting all the books, so this list should soon be updated.
See the current termcard (linked from the OUSFG home page) for directions to the library and details of library meetings.