There are lots of specialized controllers of power devices like heat controllers, pump controllers. So why not to build a universal one that would fit for most of needs. Mike have put pretty simple project based on Arduino. He took four socket unit and turned it in to programmable device.
Each of sockets is controlled individually with mechanical relays. He had written demo software that demonstrates its working and even 10Hz pwm is generated that probably isn’t best solution for mechanical relays. But for time or event based control this is good enough. If you need more flexibility like PWM functionality you should consider using Solid State Relays instead. As always – this project deals with dangerous voltages and currents, so be sure you know what you’re doing.