If you're interested in having two players play off one machine while you challenge a rival on another end then the best mode of accomplishment would be to pick up a game controller like an Xbox 360 controller and then use that as the secondary players controller. While I used to play EA's UEFA Champions League, my pal and I would play the campaign on the same machine with me on the controller while he was on the keyboard.
Arguably, two people can game off the same keyboard but with reassigned keystrokes. Think two player Metalslug. A fun experiment would be to borrow a keyboard from your friend and see if what you're trying to achieve is possible but you'll need to reassign some of the keys as that may cause an issue with...