Virtual reality applications detach the user from the real world by fully immersing the person into an artificial environment. With the help of a head-mounted display and soundproof headphones, the visual and auditory senses are limited to the virtual content provided by the simulation. Most applications refrain from representing the users limbs in the virtual experience. However, if the application requires the participant to interact with real objects, this feature can no longer be omitted. To allow an accurate representation of the extremities within the simulation, the position and pose of the hands and feet need to be determined in real-time by a motion capture system. This diploma thesis discusses the development of the VreeTracker, a hybrid tracking system that combines optical position tracking with inertial orientation sensing. Furthermore, the resulting prototype estimates the hand pose by a markerless approach. The VreeTracker is embedded in a virtual rock climbing adventure called VreeClimber. The VreeClimber consists of an indoor climbing wall that couples the safety of a virtual simulation and the haptic interaction with real objects. As a prerequisite, all necessary hardware components of the tracking system need to be affordable, easily available off-the-shelf devices. Therefore, in addition to implementing the tracking software, the development process includes all necessary modifications of said consumer products as well as the development of individual hardware components.