Pydance is a relatively simple program for Linux that's similar to Dance Dance Revolution. Dance pads are supported, but you can just play wih your keyboard if you like. The game also supports music files from other DDR-like games.
First, install Pydance.
Next, open your Home file browser and choose View -> Show hidden files.
Go into the .pydance directory.
Create a new directory named "songs" with a lower case "s."
Visit a Dance dowload site like this one.
Download songs and drag the folder with the song's name from the archinve manager into the new songs directory in .pydance.
Repeat the downloads until you have several songs.
Optionally, you could search for a free song pack, possibly on a bittorrent site (please respect copyright).
Start Pydance in Applications -> Games -> pydance.