My runs in Lexington as logged by RunKeeper. GPX files of individual runs were downloaded from RunKeeper and tracks were consolidated into a single GPX file using GPS Babel. I converted the combined GPX file into GeoJSON using OGR2OGR via QGIS 2.8.1. I used MapboxJS to pull in CartoDB's Dark Matter tiles and to generally just set up the map. Finally, I used jQuery to pull in the runs.geojson.
Next steps include:
https://api.tiles.mapbox.com/mapbox.js/v2.2.1/mapbox.js
https://ajax.googleapis.com/ajax/libs/jquery/2.1.4/jquery.min.js