Most smartphones have USB connectors made for mounting the phone as a device. Android hacker Sven Killig has figured out a way to turn the Nexus One into a USB host and turn it around, mounting other devices to the phone instead.
This hack should let you use your phone with pretty much any USB device, like a keyboard, flash drive, webcam and even an external monitor. Getting it in host mode involves quite a bit of command line work and manual kernel patching, but if you've got a Nexus One on hand and you're pretty experienced in such things, it could make your phone a lot more useful.
The hack was done on Android 2.2, though Killig notes it should work on 2.1 as well. While we expect this method could be used as a springboard for similar hacks on other Android phones, it would probably take someone with a bit of knowledge to figure it out — the specific patches look like they're phone-specific, so you probably couldn't follow the same instructions with another smartphone. Check out the above video to see it in action, and let us know your thoughts in the comments.