HSI (think CSI for history) is an absolutely great site for History teachers. It allows students to choose from one of 13 cases to go through and solve. These cases are put together similar to that of a webquest, where students have different links/downloads that they can go through. Also, there is a separate teacher & student view.
I highly recommend checking out HSI by clicking here.
I'd like to thank the Educational Technology Blog for his great review of this site.