Cellular automata are fully discrete computational entities composed of a group of simple units with local processing abilities. In spite of their structural simplicity, they can lead to sophisticated global behaviours, which renders them paradigmatic models of complex systems, as well as computing devices with universal ability. Assuming no familiarity of the audience with cellular automata, I’ll first introduce them with a few examples. Then I’ll discuss them from the computational point of view, particularly within the context of two classical problems that have been the basis of the research carried out during my visit at uOttawa. In doing so, a connection will also be established between evolutionary computation and the search for good cellular automata for those problems.