I asked a while back 'What Is Ergodic Literature'. Rogue Semiotics has the answer, and gives examples: "'Ergodic' is being used here to mean literature where 'nontrivial effort is required to allow the reader to traverse the text'. In other words, literature where the reader is either encouraged or forced to actively participate in the progress of the text. In The Unfortunates, famously, the 'novel' is a sheaf of 32 sections in a box. The reader is instructed to shuffle them into any order desired before reading".