1. In a distributed processing system including application clients that participate in an application session executed in the distributed processing system, a method of causing host duties for the application session to migrate from a first client to a second client, the method comprising the steps of: executing the application session at the distributed processing system, wherein the application clients participate in the application session, the application clients including at least a first client that has the hosting duties for the application session, a second client, and a third client; as part of the application session, storing at each of the application clients a data structure that includes a unique identifier associated with at least each of the other application clients; exiting the application session by the first client, such that the remaining application clients include at least the second client and the third client; as the application session continues, selecting the second client for the host duties based on predetermined selection criteria; and causing the host duties to migrate to the second client.