In many game-like open-ended multiplayer communities, the success of the game, and well-being of the community, depends on the efforts of certain individuals who arrange resources for gameplay to other players. These include e.g. game masters, server hosts, and fan site creators. We identify the importance of these voluntary "playmakers" by describing their activities in four communities: (1) Habbo Hotel moderators, creative room designers and fan site builders, (2) Live-action role-playing game masters and non-player characters, (3) Geocaching cache creators, and (4) Neverwinter Nights dungeon masters, player guides, developers, and server hosts. Based on an analysis of this empirical data we describe motivations that the playmakers have for participation in game community activities. Such descriptions will help to improve design for games where playmaker involvement is of critical importance to the game's success. Categories and Subject Descriptors K.8.0 [Personal Com...