Suggest a book for a milestone year

I love a big “project” book and the year I turned 40 I read Proust’s In Search of Lost Time. I read it over the entire year and it was a fantastic reading experience – memorable and special. I turn 50 next year and I’m trying to come up with a similar idea. I’ve read a lot of classics – the whole Rougon Macquart cycle, war and peace, Les Miserable, Moby Dick, the Iliad and Odyssey, Don Quixote, all of Virginia Woolf’s novels. The only thing I can think of is Ulysses, but it doesn’t sound that appealing. Ideas?