But lets not get sidetracked. The moral issue of catching animals, forcing them to live inside little balls and occasionally fight one another is for another day. I'm just here to tell you how to make one.
This is a relatively quick and cheap way to make a pokéball, either as a prop, or to store stuff in (pikachu statues). The actual making time was 2-3 hours of solid work. It's not as easy as it looks and if I had two or three days to do it, it probably would have turned out a lot better.
I'm not liable for any injuries caused making this project. I'm paranoid, OK?
If anything isn't clear, just leave a commment and I'll sort it out. Sorry for the blurry photos, it was dark by the time I'd finished and my camera's not brilliant. Also sorry for the quality of the build, I was under pressure to finish it (I did it in about five hours, including getting the materials.
Step 1: Materials
Materials I used (substitute in whatever you need to)
2 Cardboard eggs
Some kind of black plastic (flexible, but not too much)
2 Washers (one slightly smaller than the other)
Red and white paint
Small amount of (duct) tape
For the electronics
10(ish) really bright LEDs
Push to Break switch
Resistor (Calculate it for your specific LEDs here )