http://www.ted.com/talks/jane_mcgonigal_gaming_can_make_a_better_world.html

Discovering McGonigal's work changed my life: first time I heard someone else than me saying out loud that games can be good - in a bettering the world kinda way.

It's also what keeps me active on IfWeRanTheWorld, as far as I know, this platform is the closest to what I am looking for: community, action, change, and rewarding goodness. (fun, pleasure, play, games; with a tangible result)