(I'm sorry if someone else has posted this before me, by all means post a link to yours in the comments.)
Step 1: What You'll Need.
Alright, you'll need:
Two or three button cell batteries. (The thick 1.5v ones.)
Scissors. (Sorry, forgot them in the picture)
Step 2: Make the Pack.
Get your batteries, and stack them like in picture 2. The first battery has the + side facing up, then put the second one the same way on top, then again for the third battery. Then, get a 3 or 4 inch strip of tape, and wrap it tightly around the batteries, (see picture 3) making sure they are fairly tight against eachother. I find that squeezing from the top and bottom of the pack while wrapping helps keep them tight. If you don't feel they're tight enough, wrap a second piece of tape. Got all that? Good. Now, take your scissors and trim the excess tape off the top and bottom.
Step 3: You Have Two Choices...
If you chose to leave it as is, I still recommend checking out the next step to see how to hook up wires.
Step 4: Attach Wires.
Alright! So, get your wire, and cut two 2 - 3 inch pieces, then strip a bit off each end of the wires, taking a bit more off one end then the other. Now, get another 3 - 4 inch strip of tape, and tape the red wire's more stripped end to the plus side, then wrap the tape down and tape the black wire's more stripped end to the negative side, and wrap tightly.
Step 5: Fin.
So, my multimeter won't register these packs, but they do work!
I'm not sure why it won't register...
And, please, if you want to, send me a picture of something powered by this!