I know it has been created, but I'm wondering if there are any (FREE&#33 downloadable alife civilazations. You know, like an ant colony (but not the type wich is just: find food, take back home, repeat)

For those who dont know, Alife is artifical life. Related to AI, instead of trying to create a resoning robotic computer program, it is an attempt to create a program that acts like an unintelegent, or sometimes semi intelegent life form. Examples would be flocking programs.