"Orbitz' "flex search" offers a helpful feature where you can specify additional dates to include in your search (e.g. 1 day before and after the date you submit). The results screen comes with an excellent use of table cell highlighting — example screenshot here. Rollover a cell containing one of the prices and it lights up that cell as well as the relevant arrival/departure date cells."
Good UI and very practical feature when you're willing to be flexible about dates in order to save money.