If you are an intern looking for an internship in the Washington, DC startup or tech community area you should join one of many startup discussions in the area and tell people you are looking.
If you are a programmer this means you should be announcing yourself in the programmer user groups - think DCRUG (Ruby on Rails) or BMore On Rails (Ruby on Rails) or NoVARUG (Ruby on Rails), DC Python (Python), etc. Most of these are on Meetup.org. There are also some great general discussion areas like DC Tech and Baltimore Tech on Facebook. Another great group to check out is Refresh DC - this is more web agency and web development and design oriented. Refresh Baltimore is similar.
In addition, there are a ton of great places to find out what is happening in the Washington area as well as to find out about startup and tech jobs and internships in the area. Craigslist has some great stuff. SocialMatchbox.com has some great stuff. DCTechEvents.com has some great stuff. BaltimoreTechEvents.com has some great stuff. There is also a Hacker News Meetup in DC - a great bunch of people are involved in it. Baltimore has a similar group that meets up called the Hacker Stroll, they go to a lot of different events together and have a monthly happy hour.
There are tons of great tech and startup companies in the Washington, DC area. The community is growing and very diverse. There are a ton of things going on and so many different people trying to come up with ways to organize all of it that it is hard to keep track of it all. No one website has all the answers or all the people so don't miss out on that.