What all can you do with a USB connector?

I have a usb connector for my NDS, and was wondering what all I could do with it.

I haven't used the NDS in 2 years, and want to make it useful. lol

More than likely, it's just a power adapter that uses the 5v power pins from the USB port to charge the DS. The DS doesn't have any sort of on-board storage, so in order to run homebrew programs you have to buy a special cartridge and microSD card.