It was my pleasure to present "An Introduction to ROOT" at the Madison Big Data meetup on Tuesday. ROOT is a set of open-source object-oriented data analysis frameworks designed for power and scalability to large datasets. ROOT is heavily used and developed by the particle physics community (see root.cern.ch), but it's well suited to the exploration and analysis of any large structured data set. Besides particle physics, ROOT is used in astronomy, biology, finance, and medicine. I presented an introduction to ROOT with example scripts using sample "everyday" datasets.
Slides and sample scripts are onine at https://github.com/bigdatamadison/Talks-and-Sample-Code.