Something Nate Hopkins has been working on. Here is a snippet from the doc:
Goldmine allows you to apply pivot table logic to any list for powerful data mining capabilities. In the nomenclature of Goldmine, we call this digging for data. So we've added a dig method to Array. More reasons to love it * Provides ETL like functionality... but simple and elegant * Supports method chaining for deep data mining * Handles values that are lists themselves * Allows you to name your pivots * What does this all mean for you? Lets have a look.