All my creative work is published under a Creative Commons Attribution Non-Commercial License (Germany, currently version 3.0) unless specified otherwise.

That means you’re free to remake, remix, change and distribute based on my works freely, and free of charge, so long as you

1. include credit to me as the original author in an appropriate manner and
2. do not publish your work with commercial intent.

Especially the latter may make this license seem restrictive. If you would like to use any of my works and are unsure whether your use would be considered commercial, or you do intend to use it commercially, please contact me.