usb network?

i was lying in the bath the other night just pondering the universe and i thought, why cant you connect two computers via the usb port and create a basic network? i dont mean a screaming full blown network, its just that i’m short of room in my present computer (all ide full) and could use the extra space for other stuff. yes i do have network cards and can work them. i just wondered if anyone else had thought about this possibility? (57 spare points)