What is Ergodic Literature? From Cybertext: Perspectives on Ergodic Literature by Espen J Aarseth (1997) "During the cybertextual process, the user will have effectuated a semiotic sequence, and this selective movement is a work of physical construction that the various concepts of "reading" do not account for. This phenomenon I call ergodic, using a term appropriated from physics that derives from the Greek words ergon and hodos, meaning "work" and "path." In ergodic literature, nontrivial effort is required to allow the reader to traverse the text. If ergodic literature is to make sense as a concept, there must also be nonergodic literature, where the effort to traverse the text is trivial, with no extranoematic responsibilities placed on the reader except (for example) eye movement and the periodic or arbitrary turning of pages".
See also these links on computer gaming and protocols of improvision; there's a hint that ergodic gaming crosses literature/cybertext/play? Investigating.