The disclosure is directed to an interactive multi-tasker for casting applications executing on a first computing device of a user on any of multiple computing devices of the user from any of the computing devices. Each of the computing devices presents a unified view of tasks and applications executing on each of the computing devices through the multi-tasker. The user can perform multiple actions on the tasks and applications, e.g., cast using a first device an instance of an application that is executing on a second device on to a third device. The state data is synchronized from the second device to the third device. Another instance of the application resumes execution on the third device using the synchronized state data. Once cast, each of the instances of the application executes independently of each other.