Some embodiments of the present invention provide a system that presents an alternate computing environment on a host computing device. During operation, this system detects the presence of a removable storage device which is in communication with an interface of the host computing device. The system also locates code which implements the alternate computing environment on the removable storage device. Finally, the system runs the code which presents the alternate computing environment through an environment player on the host device, wherein the environment player prevents a user of the alternate computing environment from interacting directly with a native computing environment of the host computing device.