I have a bunch of figures that I wanted to wire up so I didn't ever have to change batteries or flip switches. In the past I've just used a piece of rubber but I figured I'd design something a little nicer. These let you insert a twisted wire with one coming out of each side, then you can use conductive tape as the contacts. I multi-color printed these to indicate +/- but that's optional. 
Note: obviously make sure you're power supply is correct (3v) if you're going to be using this to replace a cr1025 button cell.