Stepmania is A Game where there are 4 arrows at the top that stay still.. then other arrows in color come from the bottom and go up as you try to hit the same arrow on the keyboard that is on the screen... its sort of like Dance Dance Revoltion but with your fingers rather than your feet.
you can get stepmania at http://www.stepmania.com and there is also stepmania online at http://www.stepmaniaonline.com . and also youll need some songs my reccomendations for songs are http://www.ddrgeek.com which has a bunch of packs.. or http://shauno.filefront.com which has all the original ddr packs 1-8 and also there is http://www.ddruk.com/downloads.php?subcat=1 which has some packs in torrent files.. um look on various torrent sites for stepmania songs, theyre hard to get on torrent sites.. err and http://www.itgfreak.com/phpBB2/viewtopic.php?t=5539 that has some good packs but some links are broken. err a bunch here http://ddrforum.pocitac.com/viewtopic.php?t=64 altho its half english half something or other. but the best is ddrgeek and shauno.filefront.com . make sure u get most of the packs that are on shauno.filefront.com from ddrgeek as filefront's ones are slow. then get the ddr packs
well enjoy