Today social networks and microblogging services attract much attention and their importance and pervasion is constantly increasing. This trend is fostered by the increasing prevalence of mobile internet devices, which enable users to be online every time and everywhere. A popular kind of applications provided via social network platforms are games. While existing social network games basically realize common online game principles where each user controls a single game entity and acts on its own behalf, this paper presents a framework for the creation of a novel kind of social online games. The idea is to enable games where users do not act as individual game entities, instead groups of users control one game entity whose behavior emerges from the collective behavior of all group members. The framework is based on the microblogging service Twitter and users interact with the game via Twitter messages. These collaborative social online games are not just an innovative social network application, the intention of our framework is rather to provide a useful and powerful tool to complex social network researchers to study emergent and collective user behavior on a large scale utilizing the huge user base of a social network service like Twitter. In addition to presenting the idea of collaborative social online games along with the so-called TweetGame framework, this paper presents a sample application that has already been realized on top of this framework as proof of concept.