WARNING: This kernel module is not endorsed, recommended, or whatever the 
hell else by me or the Linux kernel team. This module may make your 
joystick cease to function or it may make it explode. No one is 
responsible for what you do with this module except YOU, the user.

Having said that, here is a module that you can use for your DDR mat that 
will make it so you don't have to turn your mat and dance on the buttons 
(all the arrows will work, and you can pretend you're actually playing 
Real(tm) DDR). I think this module requires kernel 2.4 =]

To make the module, type:

./build

For a DDR mat on 0x378 (LPT1:), try:

modprobe ddrmat gc=0,7

The ,7 will not be needed as soon as this module turns into less than a 
quick messy hack of drivers/char/joystick/gamecon.c

Many thanks to Vojtech for his help and guidance in hacking around with 
his gamecon module!