A new rechargeable battery is on the market –USBCell from Moixa -- that promises to make it even easier to charge up when not in use.
As the name suggests, these AA batteries recharge through a built-in USB connection, cleverly located under the hinged cap.
Therefore, you can use it like a regular battery in your game controller (or other gadgets and toys, of course) and then charge them up anywhere you've got a USB port, such as a laptop. No cables or charging docks are required.
While we haven't tried out the USBCell yet ourselves, these rechargeable batteries ($17.99 for a 2-pack) are said to charge to 90 percent in 5 hours, while just 1 hour of charging yields about 50 percent of power. A small LED light shows when the battery is charging, and different colors for when it's at 90 percent and fully charged.
These NiMH (Nickel Metal Hydride) batteries can be reused "hundreds of times" before they need to be replaced, says Moixa.
More info on the USBCell is available here, while stores that carry the product include Tiger Direct, CompUSA, Circuit City, Best Buy, SharperImage.com and ThinkGeek.com.