Oh, I've made one too! http://github.com/erming/shout

It's really stable (been using it for weeks without restarting) and I've even implemented a mobile interface: https://db.tt/fYTswBwO

You'll find the install instructions in the README (or just `npm install shout`). No configuration required. Should take under a minute to get it running if you already have NPM.

It's open source. Feel free to try it, browse the code and leave some feedback. If you want to work with me, it's open for contributions!