Dump and load relational objects between Ruby environments.
The project started at GitHub to simplify the process of getting real production data into development and staging environments. We use it to replicate entire repository data (including associated issue, pull request, commit comment, etc. records) from production to our development environments with a single command. It's excessively useful for troubleshooting issues, support requests, and exception reports as well as for establishing real data for evaluating design concepts.