If WW2 was fought by online gamers....
What's the highest mAh AA-size (LR6) rechargeables you people have seen? Either 1.2-1.5V or 2.4-3.0V (In the latter case, the mAh will be doubled when in parallel, so a 1mAh 2.8V is as useful as a 2mAh 1.4V battery) Don't really care about what chemistry - NiMH, Li-Ion, Li-Poly, mostly concerned with capacity. And fitting.
http://www.animalgame.com/ - A fun online game I found, much like one I used to play on my Apple //e.