Achievements is a WordPress plugin that is built on top of BuddyPress (another plugin) that awards visitors with achievements for accomplishments on the site. It’s inspired in part by gaming achievement systems like XBOX Live.
Paul Gibbs is the developer behind Achievements. You can follow him on Twitter @pgibbs.
Achievemtens runs well on my Site http://www.upgradeyourlife.at even in german. Only problem at the moment ist, that I don’t know if a particular achievement can only be earned once ore more than once. Maybe someone can help?