Setting up XAMP for ImpactJS is an unnecessary pain. Apache caches resources. Apache requires configuration. Do you really need to be running MySQL to develop a JavaScript game?
Using Python's SimpleHTTPServer causes its own headaches: it's slow, it can quickly get overwhelmed by requests and start randomly 404ing.
Since the game you're writing is in JavaScript, why not run a server written in JavaScript? Hence this project.
Do not use this server in production. It exposes Weltmeister and is not written with an eye towards anything resembling security. Seriously, just don't.
Install via npm. If you don't have npm yet:
curl http://npmjs.org/install.sh | sh
Once you have npm:
npm install impact-dev-server -g
This will install impact-dev-server globally so that it may be run from the command line.
impact-dev-server [path]
[path] defaults to ./.