Electronic gaming machines, such as slot machines or video poker machines are interconnected by a computer network. The behavior of each machine is controlled by configuring selected parameters such as game speed, payback percentage, or game appearance. As the machines are played, any of the selected parameters may be changed responsive to commands issued over the network. The commands are issued in response to predetermined changes in variables such as rate of play, player status, and the time of the day, week, or month. The payback percentage may be changed by implementing a new pay table at the selected machine or machines or by implementing a bonus period during which a percentage of all money played on the selected machines accrues in a bonus pool. During the bonus period, the selected machines are eligible for bonus awards that may be random or related to jackpots paid based on the pay tables in the selected machines.