Arduino, for those who are not avid Do-It-Yourselfers, is the most popular IoT prototyping platform of all time. 
It is the open source hardware and software platform on which, since about 6 or 7 years ago, when Massimo Banzi introduced it, thousands of projects have been developed. Here's a list of over a dozen practical Arduino projects you could build. Here's a blog about some of the strangest Arduino projects.
Even though there are dozens of books and portals about Arduino, it's still a very hot topic. On June 26, our IoT Zurich meetup group had two speakers presenting Arduino concepts and projects to over 30 people interested in making IoT happen.
Thomas Brühlmann, author of "Arduino Praxiseinstieg," started with an introduction to the Arduino platform (his slides are available here). He also showed a variety of examples and, to perhaps inspire, perhaps to embarrass us, he brought his young assistant (his son). 
Following Thomas, we had Micheal Kroll, another local hacker with really valuable experience using Arduino. Michael's talk about the Bluetooth Low Energy Shield he has built was very interesting, showing the practical experience he has with the platform. His slides are available here.
Both of the speakers and their content were really valuable for our meetup members, especially those who are preparing to come to the first special full-day event we are organizing. On Saturday, July 7, 2012, the DIY IoT Workshop in Zurich will take 10 people through the steps of making their first IoT project. Led by our IoT-Zurich co-organizer, Thomas Amberg, co-founder of Yaler, this workshop is going to provide a small group with the hands-on experience and guidance that many need to launch their careers as DIY IoT community members. Thomas has 10 years of experience building things and really knows how to communicate this knowledge in a systematic way. We have only one place remaining for this workshop, so someone still has a chance to enroll!
After the July 7 workshop, the holidays will be in full swing so the IoT Zurich meetup group will take a break. On September 5 we will be having another meeting on the topic of RFID and NFC for IoT. This will be a mix of theoretical information, about the concepts behind these technologies, and practical info, the use cases and case studies of implementations of RFID performed by Vilant Systems.
Arduino and its uses will be one of the topics again during our September 21, 2012 IoT 4 Energy Hackathon. This one day event is going to bring together several hardware and software platforms and focus the minds of our local developer community on how we can use IoT to help consumers better manage their energy consumption. There will be a great group of experienced leaders providing hardware and software to meet the hackathon's three primary goals:
- Create applications/projects that makes energy monitoring fun,
- Create applications/projects that help people become aware of their energy consumption and ultimately become more energy efficient, and
- Create applications/projects that are useful to many.
Surprising how much DIY IoT activity we can pack into a few months for those who live in a "small city" like Zurich!