I have completed Ulysses, by James Joyce.
Plot: A day in the life of Leopold Bloom, in such detail as to make you realize -- with as many things that he must have done, said, or thought, or things that affected his actions, thoughts, or words, in addition to the material included in the nearly 1000-page book -- as to make one realize that every day is just as much a miraculous journey as Ulysses's original fictional voyage.
Opinion: As literature, bemusing but amazing. The more I understand the more I'm impressed. It's more than something to read, it's an experience (some might say TORTURE and they wouldn't be half wrong). I might read it again if I ever find an annotated version, just to find out what U.P.: UP means.
Caveat: I didn't get most of it. Took me much longer than 24 hours of reading time.