This presentation is an adaptation of https://speakerdeck.com/wayoutmind/dwolla-tableau-and-aws-building-scalable-event-driven-data-pipelines-for-payments focussing specifically on how to capture flexible, semantically atomic events. It also introduces an open source Python library, https://github.com/Dwolla/arbalest and demonstrates how to compose AWS services to enable interactive querying and analysis at scale. [This presentation was originally presented at Iowa Code Camp 16, Dec. 5, 2015.]