The Day of Archaeology is an annual, 24-hour, international online event in which archaeologists and those in related fields write blog posts about their work. It was inspired by the Day of Digital Humanities and, similarly, allows practitioners of many kinds, to document their work informally and 'provide a window into the daily lives of archaeologists from all over the world'. Though it encourages diversity rather than thematic posts, the project has some similarities to Blog Action Day. From Wikipedia
