A three-dimensional virtual world simulation is described, where evolution takes place and it is possible to investigate behaviors of creatures in real-time. Bodies of these creatures are made of sticks, and their brains are built from artificial neurons. There are no constraints on topology and complexity of neural networks, as well as on the size of morphology. The model is inspired by biology, so energetic issues such as energy gains and losses are also considered. The evolutionary process can be guided by some pre-defined criteria, however, it is possible to mimic spontaneous evolution when the fitness is defined as the life span of the organisms. Interactions in the virtual world are discussed (including the possibility of worldwide-distributed simulation), and the results of so-far experiments are presented.