Open Data Kit (ODK) is a free and open-source set of tools that help organizations author, field, and manage mobile data collection solutions. ODK provides an out-of-the-box solution for users to: build a data collection form or survey; collect the data on a mobile device and send it to a server; and aggregate the collected data on a server and extract it in useful formats. In addition to socio-economic and health surveys with GPS locations and images, ODK is being used to create decision support for clinicians and for building multimedia-rich nature mapping tools. See the list of available tools, featured deployments, and implementation companies for more examples of what the ODK community is doing. We welcome and encourage participation from the user community.