XtenSRVR is an Active-X component library that allows programmers to easily use the capabilities of the X10 CP290 home automation controller.  This inexpensive controller, attached to a serial port, allows a PC to control lights and other devices attached to X10 home automation modules.  The CP290 contains memory that is used to store timed events, allowing the CP290 to control your lights even when not attached to your computer.  Information about the CP290 controller can be found at the X10-USA home page.