Once more we're back to the question, "What makes learning fun?" There are deep links between play and learning. Consider, for instance, the way we learn the rules of a game through playing it. The first times we play a card game, or a physical sport, or a computer simulation we test out rule boundaries as well as our understanding. Actors and role-players learn their roles through the dynamic process of performance. The resulting learning isn't absorbed all at once, but accretes over time through an emergent process, one unfolding further through iterations. In other words, the more we play a game, the more we learn it.
In addition to the rules of play, we learn about the subject which play represents, be it a strategy game (chess, for example) or simulation of economic conflict. Good games echo good teaching practice, too, in that they structure a single player's experience to fit their regime of competence (cf. Vygotsky's zone of proximal learning, a la Gee ). That is to say a game challenges players at a level suited to their skill and knowledge: comfortable enough that play is possible, but so challenging as to avoid boredom, eliciting player growth. Role-playing in theater lets performers explore and test out concepts; see Boal . Further, adopting a playful attitude helps individuals meet new challenges with curiousity, along with a readiness to mobilize ideas and practical knowledge. Indeed, the energy activated by play can take a person beyond an event's formal limitations, as players can assume that play can go on and on .
Douglas Thomas and John Seely Brown: "All systems of play are, at base, learning systems." 
Games have always had a major social component, and learning plays a key role in that interpersonal function. Using games to build group cohesion is an old practice, actually a triusm in team sports.
It is important to locate our peeragogical moment in a world where gaming is undergoing a renaissance. Not only has digital gaming become a large industry, but gaming has begun to infiltrate non-gaming aspects of the world, sometimes referred to as "gamification." Putting all three of these levels together, we see that we can possibly improve co-learning by adopting a playful mindset. Such a playful attitude can then mobilize any or all of the above advantages. For example,
Two friends are learning the Russian language together. They invent a vocabulary game: one identifies an object in the world, and the other must name it in Russian. They take turns, each challenging the other, building up their common knowledge.
A middle-aged man decides to take up hiking. The prospect is somewhat daunting, since he's a very proud person and is easily stymied by learning something from scratch. So he adopts a "trail name", a playful pseudonym. This new identity lets him set-aside his self-importance and risk making mistakes. Gradually he grows comfortable with what his new persona learns.
We can also consider the design field as a useful kind of playful peeragogy. The person playing the role of the designer can select the contextual frame within which the design is performed. This frame can be seen as the rules governing the design, the artifact and the process. These rules, as with some games, may change over time. Therefore the possibility to adapt, to tailor one's activities to changing context is important when designing playful learning activities. (And we'll look at some ways to design peer learning experiences next!)
Of course, "game-based learning" can be part of standard pedagogy too. When peers create the game themselves, this presumably involves both game-based learning and peer learning. Classic strategy games likeGo andChess also provide clear examples of peer learning practices: the question is partly, what skills and mindsets do our game-related practices really teach?
Socrates: "No compulsory learning can remain in the soul ...In teaching children, train them by a kind of game, and you will be able to see more clearly the natural bent of each."
Exercises that can help you cultivate a playful attitude
Use the Oblique Strategies card deck (Brian Eno and Peter Schmidt, 1st edition 1975, now available in its fifth edition) to spur playful creativity. Each card advises players to change their creative process, often in surprising directions.
Take turns making and sharing videos. This online collaborative continuous video storytelling involves a group of people creating short videos, uploading them to YouTube, then making playlists of results. Similar to Clip Kino, only online.
Engage in theater play using Google+ Hangout. e.g. coming together with a group of people online and performing theatrical performances on a shared topic that are recorded.
Gee, J. P. (1992). The social mind: Language, ideology, and social practice. Series in language and ideology. New York: Bergin & Garvey.
Boal, A. (1979). Theatre of the oppressed. 3rd ed. London: Pluto Press.
Bereiter, C. and Scadamalia, M. (1993). Surpassing ourselves, an inquiry into the nature and implications of expertise. Peru, Illinois: Open Court.
Douglas Thomas and John Seely Brown (2011), /A New Culture of Learning: Cultivating the Imagination for a World of Constant Change/. CreateSpace.
Malone, T.W. (1981), Toward a Theory of Intrinsically Motivating Instruction, Cognitive Science, 4, pp. 333-369