Systems and methods for providing a recreational game that promotes coordination, provides a form of exercise, and is an enjoyable pastime. Preferably, surface electrode includes a plurality of tissue-penetrating elements which advance into the tissue, and the surface electrode is removably attachable to the probe. Additionally or alternatively, such methods and systems may provide for analyzing modal shape or nodal configuration of a bladed disk based on a phase analysis of strain signals acquired from a bladed disk subjected to a fluid excitation, wherein the modal shape or nodal configuration corresponds to modes of blades coupled through a disc or shrouding. The boundary module determines a continuous boundary between the noisy and quiet undulations based on the samples and the sound signal. In response, the system receives a request from that client that the option to establish the session with the remote device be made available to at least one client of the plurality of clients other than the given client.