A computer games apparatus includes a server operable under the control of a computer program to generate and store data defining a 3D game environment. Objects within that environment can be moved and/or changed in response to signals received by the server from player terminals. Those signals may be transmitted via the Internet and/or other networks. The server renders the object data into data defining one or more views of the 3D environment, which data can then be processed into a broadcastable form for receipt by a plurality of observers. The performance of the apparatus is unaffected by the number of observers actually in receipt of the broadcast data.