I have recently developed a tool, mapgen, which generates interactive maps with customizable markers. It takes a YAML file containing map settings and marker data as input and generates an HTML page as output. This page contains all JavaScript and CSS code it needs inlined into it, so it can be directly opened in a web browser (without the need for a web server), shared with others (e.g. via e-mail), or added to an existing webpage through an <iframe> element. Below is an example of a simple map generated with mapgen:

The contents of the YAML file used as input to generate this map can be found here. If you would like to see additional examples or read the tool's documentation, see its README file.

Feedback and feature requests are of course welcome. Have fun! :-)