GPX is a commonly used file format to store tracks and routes. Marble can open and display such files in a map. We want to build a collection of sample .gpx files from different applications to ensure that all .gpx files are displayed in a sane way. Collect sample GPX files from different applications (see the OpenStreetMap wiki on GPX conversion for a list of programs that produce GPX files). Ideally the files are available under a create commons or similar license. See also http://en.wikipedia.org/wiki/GPS_eXchange_Format and http://wiki.openstreetmap.org/wiki/Converting_GPS_track_data_between_formats