This took about five minutes to make this. It is also recycled from old computer parts.
this is my 1st Instructable. please leave any comments!

materials: LEDS (or else this is pointless!),battery source, old power supply for a computer
(you should find some other useful stuff in it.)

tools: any tape should do or a soldering iron.

another source of recycled parts is from the old computer.
open it up,take out the two batteries in the motherboard (trust me, You'll find them.)
take one of the two front panel buttons (either power or reset) or use the switch located in the psu. It took a while to take out but I got it.

Step 1: Collecting Pieces

now you need to find the parts you need: the small(er) power cable that connects to a device (larger one works fine)
a switch. (I found one in the power supply)
separate the cable form the rest of the power supply.
if you only want to connect one led at a time, cut off two cables, leaving two. if not, leave the four on.

Step 2: Construction Part 1

1st Picture: end of the cut-off plug
if you have the four cables, twist black with black, red with yellow(it is easier that way) do not twist the cables if you have only two. either end could positive/negative. you can solder them together or leave them twisted.

Step 3: Construction Part 2: Battery Source

Now, connect the cable to a battery source by soldering or tape.
black with black, colour with colour.
If you want one with a switch, attach one to a clip the other to the power supply.
But, if you have the larger one with four clips ex:
=|=
=|=
= clips
connect one cable to one and the other cable to the clip straight across from it.
also you can do the same with the other wire.
ex: RED-----=|=-----red or wire------=|=----------
black-----=|=-----black =|=