Ho, this is legit.
-- If you are a humanities professor, you say something that is clearly pleasure-reading, but at least vaguely cerebral. Witty mysteries about British academics are good, or the sort of science fiction that doesn't have aliens on the cover.
-- If you are a university administrator, you say that you are reading the university Common Reading book, or something by one of the writers who will be visiting for the Writers' Symposium in October. Either way, it is very interesting and you are enjoying it very much.