What you will need:
44" clear 1/2" PVC pipe
Two 1 Meter LED lights (cheap at HobbyKing)
A battery (I got a Zippy Flightmax 1000mAh 2S1P 15C also from HobbyKing)
Step 1: Soldering
Solder the positive and negative wires to the lights, and then the lights to the male plug. Solder the female plug to the battery.
Step 2: Stringing and Gluing
The LED lights come with glue on them, so remove the strips of paper and glue them to each other back to back.
String the lights through the pipe so the tip of the male plug is just out the the bottom of the pipe. I glued the plug as much as possible to keep it secure. You'll have to let it sit for several hours if you want it to dry completely.
I measured an 11" handle to make room for the battery which you do NOT want to grasp while fighting.
Once the glue is dried on the bottom, pull the lights at the top and turn it, so it twists inside the blade like a candy cane. This part is tricky because you have to simultaneously hold the lights while gluing them. The glue sets fairly quickly, so after gluing the lights at the top of the blade, you only need to hold onto them for a minute or two. Obviously the more you glue, the more secure they will be.
Step 3: Glitz
Decorate the handle however you see fit. For the red lightsaber, I added these medal things (I don't know what they're called) and the weight was nice compared to the blue one. I attached the battery to the bottom of the handle with Velcro, and then taped it.
Step 4: An Elegant Weapon for a More Civilized Age
Add the bubble wrap. I did not measure how long each strip was, but whatever you think works. I clear taped the whole blade and then secured it at the top of the handle with more duct tape. After that, you're done! Enjoy!