Abstract: Device, system, and method of interactive game. For example, a system includes: a server to host a virtual hub associated with a plurality of spokes, wherein each spoke leads users to a plurality of virtual worlds having a common characteristic, wherein the virtual hub and the spokes comprise a virtual worlds network, wherein the server comprises a single sign-on module able to receive from a user a first set of sign-on data items, and able to sign-on the user to a first virtual world and to a second virtual world.

Abstract: An unstable receptacle for storing a volume of a liquid, including a container and a closure arrangement. The container has an opening. The container is configured for holding the volume of the liquid. The container is formed, such that, when the container is placed in any orientation upon a level surface at least a third of the volume of the liquid spills out of the container. The closure arrangement is configured to seal the container.