"X-10 modules are devices that plug into an electrical outlet and allow you to remotely control the power to a lamp or an appliance that is plugged into them. There are also X-10 modules that install in place of wall switches to control lights, and there's one that can be used to set back a thermostat."
These
X10 folks make a really cool dongle called the Firecracker. These allow for the control of X10 devices via a serial-port of your PC. Programs like bottlerocket
and gtk-x10
allow Linux programs to control X10 devices using the Firecracker device. You may be able to get the Firecracker, a remote control,a receiver, and a lamp module for as little as $5.95 U.S. (special promotion).
Turn that light off when not in use!