One topic with lots of possibilities is to use evolutionary algorithms to evolve strategies for game playing. People have used evolution to generate strategies for poker, checkers/draughts, Go and many other games. The J-GAP people have used genetic programming to evolve bots for Robocode.
I recently posted an introductory article about evolutionary computation. It includes details of some of the things evolutionary algorithms have been used for. Adam Marczyk has also written an excellent article with lots of examples. The Genetic Argonaut blog contains dozens of links to interesting evolutionary projects.
A less common type of evolutionary algorithm is the learning classifier system. This evolves a set of rules for classifying inputs. It can be applied to the same kind of problems that neural networks are used for. It could be interesting to develop an LCS for a particular problem, such as attempting to predict sports results based on form.