In the past I was asked several times to write technical information (mainly about Ruby) on real paper. The results were published in magazines and books. I'm not actively looking for author projects. Nevertheless, if you have a project in mind of which you think it fits my expertise, get in contact with me.
In 2007 I wrote the german book "Ruby - Das Einsteigerseminar" (ISBN: 978-3826674594). This is a starter book for the Ruby programming language (version 1.8). It contained next to the introduction of the language itself an exercise area for each chapter and a project (photo management software) written from scratch in Ruby.
Together with Florian Gilcher, I wrote in March 2009 the cover article "Ruby die 1.9te" for the german Ruby Magazin RailsWay. We covered the syntax changes since version 1.8, the regular expression machine called Oniguruma and introduced the new encoding system in detail.
In May 2009 we (Markus Prinz and me) wrote the article "Wie das i vor den Rubin gelangt". This was also the cover article of the german Ruby Magazin RailsWay and covered the Ruby integration of MacRuby inside of Mac OS X. We illustrated the usage of MacRuby by programming a demo application to learn kanji on the Mac.
After my trip to Japan in July and September of 2009 I wrote two articles for the german Ruby magazin RailsWay about the RubyKaigi and RubyWorldConference.