Another recommendation is cellular automata, perhaps combined with some evolutionary algorithms (like genetic algorithms, genetic programming, etc)...

You can use a functional language to program them, or any other kind of language of your own choosing.

You could write your own from scratch or using any one of many libraries to do some of the heavy lifting for you and concentrate on higher level problems.

There's a lot of literature and research on all this, so it's not at all hard to get started if you're in to programming already.