Ability to control things remotely gives different level of experience. You are not dependent on wires and location. Timofte Andrei have built home automation system which can be GSM controlled. He planed his needs and came out with lighting ans heat control. Optionally he added garage door control.
Circuit is rather simple – An Arduino clone interfaced to SIM900 GMS shield. Devices are controlled by using relay module. DS18B20 1-wire sensor measures temperature that is also visible on LCD. Home automation system accepts SMS based commands. For instance “temp” which makes Arduino to reply SMS with temperature value read from sensor. Currently it has four things in control, but it can be easily extended to do more complex home automation tasks.