I read a tutorial by Jer Thorpe on the introduction to Data Visualization which inspired me to try out a simple data visualization. The data is from a code repository which includes how many developers worked on a project, the day and time of committing a piece of code to the repo and which files changed.
This simple punch card style visualization is not enough to understand without some context. The intensity in colour represents a combination of a single commit for an active project day. The total squares represent how many days the project development was going for. Thus the patterns visible shows when a project is most actively in development.