When my desktop computer was running Ubuntu 12.04, my PS3 controllers would work with USB. I didn't need to do any special setup. I could just plug it in before I start SuperTuxKart and it would recognize it. I can also do this on my laptop (still running 12.04). Since I gave my desktop a fresh install of Ubuntu 14.04, the controller would never work. I have played with some installed software that I found when looking for information. Here is what I get with xboxdrv:

liam@Liam-CustomDesktop:~$ sudo xboxdrv --detach-kernel-driver
xboxdrv 0.8.5 - http://pingus.seul.org/~grumbel/xboxdrv/ 
Copyright © 2008-2011 Ingo Ruhnke <[email protected]> 
Licensed under GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> 
This program comes with ABSOLUTELY NO WARRANTY. 
This is free software, and you are welcome to redistribute it under certain 
conditions; see the file COPYING for details. 
Controller:        PLAYSTATION(R)3 Controller
Vendor/Product:    054c:0268
USB Path:          003:012
Controller Type:   Playstation 3 USB

Your Xbox/Xbox360 controller should now be available as:
  /dev/input/js0
  /dev/input/event16

Press Ctrl-c to quit, use '--silent' to suppress the event output

So the existence of this controller is acknowledged at on my computer. But it never works for input. In my old installation, I didn't even need to get software like xboxdrv for it to work. I have never tried bluetooth on either computer, but I don't think I even have that on my desktop.

So now, how do I make my gamepad work in Ubuntu 14.04?