Libraries

• AndroidInfraRed
  Open source project for transmitting signals via IR-blasters on Android devices.
  Link

• AppIntro
  Android Library that helps you make a cool intro for your app, like the ones in Google apps.
  Link

• ButterKnife
  Field and method binding for Android views which uses annotation processing to generate boilerplate code for you.
  Link

Service

• Sunrise-Sunset.org
  Sunrise-Sunset is a free online tool that provides users information about day length, twilight, sunrise and sunset times for any location on the world.
  Link