Every two years, Ravelry hosts the Ravellenic Games, a two-week event timed to coincide with a certain global sports competition. The idea of the Games is to challenge yourself by starting and finishing crochet/knitting project(s) during the timeframe of the games. You join a team, and win medals for your team (and yourself!) by completing projects in various categories (‘events’) using various techniques (‘laurels’).
For further details and step-by-step instructions, see the Team PlanetJune FAQ.