I like to read a very seasonal book each year or so. I've often done one Gladys Taber in past years -- last year was Stillmeadow Calendar; even though I don't always agree with her she's usually very peaceful as well as interesting. This year I'm trying a new-to-me author and have really enjoyed it already: Edwin Way Teale's A Walk Through the Year. I can see why he won a Pulitzer for some seasonal books I just ordered through Abebooks. (All these books are out of print!) For several years I really enjoyed Nigel Slater (in print, yay!), especially his Kitchen Diaries 1, which had fun food shopping notes.
Your calendar can be as unique as you are – for example, you can make up your own names for days of the week, you can have say a 3-day week rather than a 7 (though you'll have to keep track of "normal" days for a job or school etc), and you can celebrate your own holidays. Two things that have really changed my life for the better are creating and celebrating my own holidays, and keeping track of them in a looseleaf notebook with 1 page per day. I feel much more free and myself!