The Turtle Recall Reading Challenge is all about Terry Pratchett's Discworld books. These are books that have been recommended to me over and over and I have yet to pick one up. This should provide some motivation for me. There are different challenge levels that can be found here. There are 41 Discworld books and I am going to shoot for the first level - The Counterweight Continent - which is 1-5 books.
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There is also a goodreads group that you can join.