Lately I've seen a lot of commenters asking questions like who their advisory neighborhood commissioner is and who their councilmember is. A good resource I often look at is the city's DC Guide "Where You Live" site, where you can type in your address and find out what police district you're in, your school zones, elected officials, and more.
You can also use the site to find out real estate values (how much is your house worth? How about next door?) and travel directions. It's a pretty cool site, and I recommend it.
There's also a bunch more if you go to the DC Guide dropdown on the front page of DC.gov.