Claude Shannon is among the most significant mathematicians of the 20th century, and nothing I have heard about him in the past thirty years has dissuaded me from this view. His ideas about condensing information and sending it along wires dominate the computer communications industry on which everything now depends. Here is a book on him,
He spent his spare time inventing and making clever toys, juggling, playing with his kids and riding unicycles. A life devoted to intelligent play. He was also a first rate investor. He spent very little time doing useful work. Everything in the computer world has vindicated his 1948 paper on the limits of what can be communicated.
If that does not make you interested in Claude Shannon, nothing I can say will suffice.