One site at Publication Aggregator is
http://dc-area-travel-deals.publicationaggregator.com/
The site’s Facebook group is at:
https://www.facebook.com/DCAreaTravelDeals/
its updated automatically reposting various travel deals for the Washington DC area. Most of the sources publish their information on Twitter or their websites, when you click a link you should be directed to the the source for more details.