bunnie has a long history of doing really cool things in hardware hacking, his book Hacking the Xbox is a great read (he has another book in the works too ). bunnie and xobs presented a complete tear down and reverse engineering of sd cards at 30c3, at 33c3 they were back talking about their education project chibitronics .
bunnie's talk is about the project it self, technical design and motivations, if the front matter of the talk turn you off believe me when I say it is worth powering through and watching the whole thing.
xob's presents an excellent session of bit banging out usb from a low power Cortex-M0+ microcontroller. This talk is a great introduction into the low level details of the usb protocol.
Reading: Babylon's Ashes