This work aims to present a historical overview and analysis on the current technical details within one category of Augmented Reality systems – Mobile Augmented Reality (MAR). In addition, this research shows what practical and enjoyable mobile applications can be made with MAR. A sample application has been developed for demonstration. The general aim of this sample application is to develop a room number recognition system using Augmented Reality technology. The work has demonstrated that an Android mobile phone equipped with this sample application can overlay augmented room schedule onto the mobile screen. Several experiments were carried out to evaluate the application. Recognition rate is an average of 91% in continuous real time testing. The application is also tested for varying viewing angles as well as different distances between the hand-held device and the targets to be tracked. Some cases of failure have been identified and shown. Future work and results of an evaluation are also discussed.