The .net repeater just renders controls to the page, once those controls are rendered anything that happens without a post back is javascript or some similar tech. Use the repeater to create the things, and have the start date in a div inside each repeated item. Then when the page renders, have a start up script to look for all the divs, get the dates out, and start running that code on that site. The JS will start updating the text/dates and boom! done. The repeater is a server side control, you need client side JS.