Every year the Free Open Source Conference (FrOSCon http://www.froscon.de/startseite/ ) in Sankt Augustin (near Cologne) is a huge success bringing the open source community together. With a very low entry fee (5 Euro last year) the whole conference is driven by personal engagement and some sponsors paying for their booths.
Beside the interresting talks there are always project rooms, workshops and booths from open source projects an intiatives. For open source projects a booth is free of charge.
As I see the opentechschool perfectly fitting there I would like to see that we make a booth and present us to the people. The goals imho would be to get known better in the tech community, engage others to launch an opentechschool or help coaching and connect with other projects like https://www.teckids.org (which do workshops for kids at the conf).
I will be there. But to run a booth several people would be needed. So if anyone is interrested in helping out with the booth I would love to hear from you.
When we are enough people (I would say we should be at least 5, so it possible to attend the conference from time to time) I will talk with the orgateam to get this started.