I was already a fan of the Robot, Foundation and 2001 series but he did loads of other cool stuff that I had no idea about. I never realised he was president of the American Humanist Association, or wrote books of jokes! The thing that really caught my eye, given my original motivation for quest, was that he suggested his own calendar reform “called the World Season Calendar. It divides the year into four seasons (named A–D) of 13 weeks (91 days) each. This allows days to be named, e.g., “D-73” instead of December 1. An extra Year Day is added for a total of 365 days.” [Quoted from Wikipedia.]
I quite like this idea - must look into it some more. (And track down some of his religious jokes!