The Arduino is an reasonably priced open source device with a tone of support. They are relatively easy to program using the dedicated and free Integrated Development Environment and can be used on a PC, Mac or Linux.
@Sheetal: Every year we use LED lights bought from the shop, it will be great to build something on your own and then you can keep getting better year after year. How do we get started?
The NeoPixels strips from Adafruit that Steve is using are great -- you buy them by the meter and they come in a waterproof plastic sleve so you can use them outside. You can get them with 30, 60, or 144 pixels per meter -- I'd probably stick with the 30 pixels per meter for what you are doing.
The really great thing is that you can control multiple meeters using a single pin on an Arduino -- and you can have multiple strips each using its own pin.
@Sanjib: Hope Cybil was not in playful mood while you were fixing those panels & wires...
My wife has two cats -- Coco (a.k.a. Coconut) nut and Drummer (a.k.a. Harrogate) -- as soon as I get my soldering iron out and layout my components and wires and suchlike, they both bounce up on the table to see what's going on -- grrrrr
@Steve, Yes in India we have very big festival of lights around October and every household is decorated with lights. Every year we use LED lights bought from the shop, it will be great to build something on your own and then you can keep getting better year after year. How do we get started?