The only comedy place I've even seen around here is that Sports comedy thing in Ballston mall, if that's even still around.
A quick search found the following places:
Wiseacres Comedy Club - in the Best Western Tysons Westpark Hotel 8401 Westpark Drive, McLean, Virginia ... wiseacrescomedyclub.com
Crystal City Comedy Club, Annandale, VA 22003, Phone: (703) 256-8849
Jammin Java in V
Forum: Fairfax County General