The best way to experiment with a new component framework is to create components, and a simple Map component is often one of the first candidates that come to mind.
In this article, I share a Lightning Map Component built with the popular Leaflet open-source library.
Step 1: Import Leaflet as a Static Resource
Download the latest stable version of leaflet here (0.7.3 at the time of this writing).
In Setup, go to Build > Develop > Static Resources, and click New.
Specify leaflet (all lowercase) as the Name, click the Choose File button and select the leaflet zip file you just downloaded.
Step 2: Create the Component
In the Developer Console, click File > New > Lightning Component. Specify MyMap as the bundle name and click Submit