A new Facebook game was launched on June 21 by a renewable energy provider as part of a marketing competition and reflects the growing trend of using games on social networks to promote environmental awareness. The new game tests players\' knowledge of solar power and offers contestants the chance to win a variety of prizes. The sharable Facebook game Solar Discovery was launched by solar energy provider Sun Power as part of a competition to win a solar system and other prizes. Players of Solar Discovery have to test their knowledge of solar power by answering a series of questions, new questions are added each week and prizes are allocated by means of a bi-weekly draw. Both the game and the competition run until September 14. The game has been criticized by some green media outlets for offering plane tickets, which are not particularly eco-friendly, as prizes. Other games on Facebook with environmental themes include eMission, Oceanopolis and Ecotopia. Essentially each of these games works along similar lines: players are given a virtual habitat or area to maintain and earn rewards by completing \'green actions.\' In the continuing merging of online and offline worlds, players of all three games are also rewarded for performing \'real world\' environmentally friendly acts which can be verified through Facebook by friends or via images.   Solar Discovery - http://apps.facebook.com/sunpowersolargame/ eMission - http://apps.facebook.com/emissiongame/ Oceanopolis- http://www.facebook.com/oceanopolis Ecotopia - http://www.facebook.com/ecotopia