Links to theaters and concerts around Washington

Friend of mine gave me these links:

http://www.worldaffairsdc.org/
http://tastedc.com/
http://www.roundhousetheatre.org/
http://www.cato.org/index.html
http://www.bluesalley.com/index.htm
http://www.kennedy-center.org/
http://www.bsoatstrathmore.org/

Do you know other links to Washington - Baltimore shows or theaters.