I enjoy speaking at tech meetups and conferences and have done it on many occasions and on a variety of topics.
Server APIs for apps
Starting at the Appsterdam Weekly Wednesday Lunchtime Lectures, Daniel Salber have given a talk on servers and apps talking together several times. I gave a version of the talk by myself at the Microsoft TechDays GeekNight.
The app development business
I was a panelist at ICMB 2012 Conference on a panel about mobile businesses and the rise of app developers. I was invited back to TU Delft several months later and gave a talk on the business of mobile app development to students from the ICT Management and Design Masters program.
I gave a lecture about open data and the city to Hogeschool van Amsterdam students. A month later I spent a day advising the students on the open data app concepts they were developing for their final project. Similarly, I gave a presentation on data mashups at the NPO Mashup Day in 2009.
Learning developer skills
I gave a talk in 2011 at Dev Haag about the basics of programming. I have also participated in some Decoded events in London, including helping teach a workshop on programming to teenagers. Most recently I gave an introductory workshop through Gidsy on how to use the command line. I will give the workshop again at Campus Party in Berlin on 2012-08-22.
I gave a little presentation on how I do Scala development at CPH Scala in 2011. I gave an introduction to Lift at a DuSE meetup in 2010.
Hackathons and meetups
I have also given a bunch of talks at various meetups and dev camps. My Quantified Self Amsterdam talk on productivity tracking has proven surprisingly popular and I gave a reprise of it at the Quantified Self Europe 2011 conference.