I'm very sorry about the quality of both the pictures and the Ible itself... I promise to do better next time ;)
Step 1: Materials
An X-acto knife, or pocket knife.
A foam ball, like the ones sold at craft stores. Whatever size you like.
Hot glue gun, and glue stick.
A few feet of wire, both red and black. (Or other color combinations if you like, just remember which is positive and which is negative.)
A 9v battery, and snap.
A full roll of packing tape.
LEDs, any color and amount you like. (As long as you can power them with a 9v battery, or get a AA battery holder)
Soldering iron, and solder. (Sorry, forgot a picture of these.)
Electrical tape. (Forgot a picture of this too...)
Fine grit sandpaper. (from 320 - 400.)
A snack! (Optional, but I was really hungry while making this.)
Step 2: Make the Balls.
P.S.! You can use this "molding" method to make other shapes. Say, a banana. Just make sure you're okay with cutting into the object before you tape it up. (If you make a tape banana, and place it outside somewhere, take a picture and comment the picture in the comments, I'll sub to you =P (I can't give out patches... >.<))
Step 3: Diffuse and Wire the LEDs.
Okay, take the sand paper, and your LEDs, and go to town sanding them. Sand them enough so you can't see into them anymore.
Now, on to wiring them. Since I'm using three 3v LEDs I'm putting them in series without a resistor (I know.. I know.. It's always good to have one... But I didn't). Cut about 6, 6 inch pieces of wire, and go from the negative leg of the first LED, to the positive leg of the last LED. Cut a shorter piece, and solder it to the positive snap wire, then to the positive leg of the first LED. Then a long piece of wire that goes from the negative leg of the last LED to the negative wire on the snap. If you need help, look at the poorly made (by me) diagram in the second picture. Notice how, if it were upside down, the LEDs would be hanging? Try and solder it so they hang like that.
Test them before going any further. Plug in the 9v, you got light? Then you're golden!
Once you're done, put electrical tape around all the solder joints, except the LED legs.
Step 4: Putting the LEDs in the Balls.
Step 5: Finish!
I hope you liked it, and have fun with your lights!
And again, sorry about any bad pictures, or instructions.