DetailsView the NPR SIMILE Timeline (Note: this script also allows you to create the necessary code to put a timeline on your site) View a presentation about how the timeline works. This script owes an incredible amount to the NPR Digital Media team. You can find out more about the NPR API here. You can also read about what they're up to on their blog Inside NPR.
This project equally owes a great amount to the Simile Timeline project. You can read the documentation here, or ask a question about the timeline widget here.