some ideas for small artificial life prog?

I'm going to work on an artificial life program in LISP.  Text-based, will write the parser-renderer in C later.  I've seen a lot of AL programs; being just grandiose state machines I'm pretty sure writing one would be within my capabilities.

...but I don't want to write a cookie-cutter one either that's just full of animals eating each other and mutating.  I'm not looking to write Spore, but I am seeking some ideas.  What are some concepts that haven't been explored too deeply in AL programs that would be interesting to see attempted?

>>1
I recommend the following algorithm:

for (;;) {
    p = penis_size
    a = RandomAction()
    ExecuteAction(a)
    while (penis_size > p) {
        p = penis_size
        ExecuteAction(a)
    }
}
ExecuteAction() sets the penis_size to a number which is calculated with some function where you take into account the number of resources or accumulated happiness you have versus everybody else's. This will implement the Will to Power.