You can find most of the code that I develop and maintain on github.com/ahornung. See below for a short overview of some larger projects.
3D Mapping with OctoMap
The OctoMap library provides a compact and efficient C++ data structure for mapping 3D environments, e.g. with mobile robots. I am the co-developer and current maintainer of the project, which is available open-source at GitHub under the BSD license. See octomap.github.io for more details.
Humanoid Robot Navigation for ROS
humanoid_navigation provides navigation capabilities for humanoid robots using the Robot Operating System (ROS). It includes navigation planning (2D path and footstep planning) as well as probabilistic localization in 3D.
ROS driver for the Nao Humanoid
I originally developed the ROS driver for the Nao humanoid robot (C++ and Python). As of now, the driver continues to be developed and maintained by Aldebaran Robotics and the community at github.com/ros-naoqi. See http://wiki.ros.org/nao for an overview of the Nao humanoid in ROS.
Some extensions that I developed for the content management system Joomla in the past. They are not actively developed anymore, but I'm happy to integrate patches. You can also find some of my contributions in the gallery component JoomGallery.