Technically yes you can, an xbox controller use's a custom designed USB plug. The catch to this is you would need to modify either the controllers plug to use the standard USB design or an adapter of some sort.
I know this because i have 2 original xbox consoles, both soft-modded with XBMC, one has a modified joystick port with an added PC type USB jack just for USB controllers which i added to the console.
Google for xbox USB conversions or controllers... If thats what your looking to do.. but.. USB controllers are pretty cheap to buy.
My xbox mod's were more about just saying FU to Microsoft , one of my xbox's also has a 360G harddrive which isnt that big by todays standards but was at the time of the mod.