If you're new to DC or have been here awhile, here are a few apps to help you navigate the town:

RideScout App - http://www.ridescoutapp.com/ - get from Point A to Point B using almost any travel method

Postmates - http://postmates.com/ - get food (and more) delivered via local courriers

SpotCycle -  https://www.spotcycle.net/ - to use with your Capitol BikeShare Program

ParkMobile - http://us.parkmobile.com/ - sign up and pay for almost any metered parking spot around town

Washio - https://www.getwashio.com - laundry...done - picked up and delivered. Ask us about our discount code

Instacart - https://www.instacart.com/ - deliveries groceries from 4 local grocery chains

National Mall App - http://www.nps.gov/nama/photosmultimedia/app-page.htm - Great for getting around the Mall and Museums