Personal use ebook
Three Men in a Boat -- I'm not sure what it's about but I will enjoy reading it, perhaps while on a boat.

Jerome, J. K. (1889). Three men in a boat (pp. 1-554). London, England: Simpkin, Marshall, Hamilton, Kent & Co. Retrieved June 10, 2011, from The Project Gutenberg eBook.

Educational use ebook
CK-12 Geometry Flexbook -- Basically a geometry textbook to use as a resource.

Wagner, S. (2011). FlexBook: CK-12 geometry (Vol. 1). Palo Alto, CA: CK-12 Foundation. Retrieved June 10, 2011, from http://www.ck12.org/flexbook/book/805/