Discrete optimisation for fun
I have mentioned Bob Bosch and his mathematical art before; recently the (US) National Museum of Mathematics released a video on Youtube of Bob giving a lecture there on some of his work ("Math Encounters - Life is Beautiful: The Startling Consequences of Three Simple Rules") It is a lecture on creating artworks that use patterns from John Conway's "Game of Life" as the building blocks and using discrete optimisation software to lay out those patterns in a picture.
I thoroughly recommend it! There is a plug for O.R. during the lecture and the first person in the audience to join in the questions (at 1:13:14) expresses delight in that publicity.
As an undergraduate maths student, John Conway taught me Number Theory.