What to do with a bunch of slightly depleted 9V batteries?

[Joe Horn]

(08-08-2014 07:34 PM)Dave Frederickson Wrote:  

(08-08-2014 06:40 PM)everettr Wrote:  If you don't include a series resistor in the circuit, neon bulbs make great short circuits! I learned about current-limiting as a child when I poked the leads of a bare neon bulb into an electrical socket. There was sound and heat, and as the spots slowly faded from my vision, I remember being slightly puzzled by seeing how short the leads had become.

As I recall my experience, it was a 2W resistor that didn't seem to have any purpose being in my nightlight.

I first learned about electrical resistance by sticking a bobby pin in the AC socket, when I was a toddler. It melted and burned a hole in my hand. One of my earliest memories.

Back to OP: AAAA cells (extractable from 9V batts) are used in some elegantly thin laser pointers.