Hadur - HADUR is a free mobile location based multiplayer game for Android, iPhone, iPad and Windows Phones.
GSAK (Geocaching Swiss Army Knife) - GSAK is the all in one Geocaching and waypoint management tool.
OUTCATCH - OutCatch is a free-to-load treasure hunting game, inspired by geocaching, adventure movies, and an old Finnish board game called 'Great Star of Africa'.
c:geo - c:geo is simple yet powerful unofficial geocaching client for Android devices.
Badge(r)s! - The game all about collecting, sharing and creating virtual swag!
iCaching - iCaching is the all-in-one Geocache manager for the Mac.