The summer is in the air and if you are not currently reading a book, maybe you will get a good opportunity over the next weeks. I, myself, just finished a great book that I can recommend you.
But of course it is difficult to recommend you anything without knowing you better. Are you used to read long and complex books or is it difficult to concentrate on 280 characters on twitter? Wherever you are are reading-wise, I found a funny little approach taking into account three factors:
Pages, ratings by other readers and Lexile score. The two first are probably self explaining while the latter measure the “difficulty level” of books by looking at how long words and sentences are. While the Lexile measurement is not perfect, it does provide some guidance for the reading level.
I found the data for 36 classics and plotted them:
The blue boxes indicates the ratings and bigger boxes are better. It is the relative score and all of the books had pretty good ratings so even a "poor classic" is probably still a pretty good book. If you haven't read anything for a while you could probably start in the lower left and vice versa if you want a challenge.
Interestingly, Night by Elie Wiesel seems to be both the easiest of all of these classics and also the one that is highest rated. So this data driven approach would recommend you to start right there!
If you have read any of the books that can also give you a feel for the ones nearest. I have for instance read 1984 and enjoyed it so One Flew Over the Cuckoo's Nest should probably be an easy challenge while A Clockwork Orange would take more of me.
I hope it was interesting to read for you and maybe'll help you find your next book. If you have any comments or questions, I will be happy to hear them.