The use of public transport vehicles, such as trams, buses, and taxis as an advertising space is increasing since several years. However mainly the outside of the vehicles is used to show advertisements using paintings, foil or roofmounted displays. Nowadays, with advances in display technologies, small highresolution displays can be easily embedded in vehicles and be used for entertainment or advertising purposes. In this paper we introduce an interactive context-ware advertising system designed for cabs, which is targeted to offer context-aware information such as advertisements, points of interest, events, etc. during a cab ride. Additionally it is possible for advertisers to upload their contents and define areas where their advertisements should be shown.