I don't often encounter the words "philosophy" and "fun" right next to the term "algebra." Nowadays, these words don't seem to fit together comfortably. However, the three terms do appear in the title of an engaging little book called Philosophy and Fun of Algebra, written by Mary Everest Boole (1832–1916) and published in 1909.
I discovered the book while browsing the online Cornell University Library Math Book Collection (http://moa.cit.cornell.edu/dienst-data/cdl-math-browse.html), which consists of more than 600 volumes that were scanned from originals held by the library. The collection includes a number of historically significant works, by such prominent mathematicians as Jean Bernoulli, René Descartes, G.H. Hardy, and Henri Poincaré, many in French, German, and other languages. It also has a smattering of mathematical curiosities. I have my eye on How to Draw a Straight Line: A Lecture on Linkages by A.B. Kempe and Euclid and