Grinch

The grinch is one of a number of controllers for on/off control of christmas lights.
It is the least expensive of any of the current designs.
It is very basic and is the easiest and quickest to build.
It does not dim lights only turn them on and off.
It is suited to direct control of individual LEDS

The grinch is just one part of a light control system and requires additional pieces to operate.
A computer controls it by a cable from the printer port.
It then sends signals out to a set of Solid State Relays (SSR's)
The grinch can operate up to 16 of the standard DIY SSR's and each of them has four channels. This give you 64 channels of light control from one grinch.
They can be connected together to add additional channels by another cable between them.
The grinch requires a 5 volt power feed to it either by a seperate two conductor power cable or it can be supplied over the same 8 conductor data cable(standard cat5 network cable like on your computer looks like bigger phone cord). It can be supplied from you computer or from an seperate device to power it.
The boards can usally be purchased from the user WJOHN on the board here if you PM him. It has very few parts and the list of parts needed is contained in the construction manual created by John here [Grinch Forum at DIYC] There is some technical information but after this you will find the parts list on the bottom of page 3 and a very good step by step instructions to assemble the grinch following that.