This is just a thread for show I DO NOT recommend trying any of these
Mods
1)
LED Light Change in Controller 
Those are the original LED lights found in the controller
What the people did is removed them and replaced them with new LED lights of a different color using a soldering iron.
Here is video if your really curius of how they did it
http://www.llamma.com/xbox360/video/...STALLATION.wmv Written Directions
With the circuit board exposed we can get down to the detail. You will need to remove four LED's they can be found around the upper center of the PCB
To get our first one done it required two people. One with the tweezers and each with an iron. Irons set to 550 F, get a good grip on the LED and a quick touch to the solder from each side simultaneously did the trick. We then busted out the hot tweezers we have never had occasion to use before and found that a much easier option.
But if you are doing this alone we found the slickest way is to bathe the LED in solder and use the iron to wipe it away and then just deposit it on your sponge. Its important to clean up after, you do not want much solder on the pads during reinstallation. And of course, be careful not get any on the sensitive gray black pads in the area.
Re-installing is much easier and a one man job, like any other tiny SMT component line it up, tack one side and then the other. They do sort of have a tendency to float up and if there is too much solder left so don't be afraid to offer a little gentle down force while heating the solder. Note the polarity marks for the led and make sure to put them on the right direction.
The final product
2)
Changing the LED lights of the xbox symbol
To change this it requires a shitload of work and concentration along with a ton of steps so ill just post some of the steps.
Again Just a process of rewiring and replacing LED lights.
Written Directions
Start by making some room for the led leg wiring by snipping out some of the support of the button. Make sure to leave a bit in the middle for strength and to give you a reference of how far you can fill at the end. I like to leave a plus sign in the middle for a handy way to remember which way the led's should be wired.
Stick the tip of the glue gun in a hole and squirt some hot glue in to about 3/4 full. The idea is to fill the hole but not so far that you don't have room to work and keep the level low enough so the button still works properly. Insert the led with the LONG leg toward the center plus sign.. get it positive
You want to push the led in far enough so you have room to work but not all the way to the front so the light spreads well.
You should end up with something like this. Note the plus in the center and the long legs all set closest to it.
Now you want to start folding and trimming the legs in a way that forms a ring with the legs touching one another. The key is to make the ring of legs lower than your center plus sign so your level will not be to high. Look at the photo and note where you want to start and finish the outside ring. You want to leave a gap between the larger of the keyed tabs of the button. The wire will eventually run out of that gap in the control case.
Now go through and solder all of the joints of the ring and create a connection between all of the led's. Remember there is a inner ring and a outer ring that should not be connected to each other.
Next solder a wire about 6" long to the inside ring. This will be your positive lead, remember the plus sign you left Again you want to place the wire so that it will be running over the larger of the keyed tabs.
Now attach a 6" long wire to the outside ring which is negative.
Position your wires so they are running out over the larger of the keyed tabs.
If you have done it right you should have some open space where you were wiring and the center plus should be the highest area inside the button. This is a great time to hook the led's up with the proper resistor for the parallel led's you have just wired and make sure the whole thing works. After you have verified that everything is working ok you can fill any extra space with hot glue. MOST IMPORTANT, you must not fill the button past the center plus signs level. If you do the button will always be pressed and will not work properly. I just happen to have the perfect tool for making a nice clean level surface on the inside of the button.. it is a large X-acto knife's butt end. I'm sure you can find something that will work.
Now place your status ring and the guide button back into the controller with the wires exiting the button area through the large gap in the status ring. Leave a very small amount of slack for button movement and tack the wires into the crack like so.
Next grab your controller PCB and flip it over and look where the USB cable connects to the board. Note which contact is red and which is black. Connect to the red positive lead the proper resistor for the amount and configuration led's (this was four blue led's so we used a 22ohm resistor). Now connect your positive wire from the guide button to the other end of the resistor. Next connect your negative wire from the guide button to the black negative lead of the controller.
A little dab of hot glue will keep the whole works in check and make sure nothing can short. You can now plug the controller into the USB port and it should be gravy.
Reinstall all of your buttons, rubber contact pads, thumb stick, d-pad and front and back pieces. Then place the controller PCB board onto the top case. When closing this part of the controller take note of the photo and make sure your wires are free and clear of the screw hole and standoff area so you don't end up with shorts or cut wires. Get it all back in place, replace your rumble motors, slap your back cover on and your in like flint baby.. your all done!
Final Product
It is also possible to light up the bottons including the start and back but im not going to include those.
3)
Adding Buttons
Poeple have added buttons to match the look of the original xbox controller with the white and black buttons on the side.
To do this you just have to rewire the controller a little bit but ill just post the final product.
Controller with White and Black buttons
Its is also possible to put a button for a direction on the D-Pad
Modding Your 360 
Linear Mode
