Consider the multi-user virtual worlds of online games such as EVE and World of Warcraft, or the multi-user virtual world of Second Life. Suppose a player performs an action in one of these worlds, via his or her virtual character, which would be wrong, if the virtual world were real. What is the moral status of this virtual action? In this paper I consider arguments for and against the Asymmetry Thesis: the thesis that such virtual actions are never wrong. I (...) also explain how the truth of the Asymmetry Thesis is closely aligned with the possibility of what Edward Castronova has called closed synthetic worlds. With some qualifications, the ultimate conclusion is that the Asymmetry Thesis is false and that these closed worlds are impossible. (shrink)