The DDR style pony mod for Stepmania has released it's third installment. Trotmania III Expands upon what the previous ones brought along, with a bunch of new songs and skins for your feet or fingers to tap to. They even have a storyline:
The third release of the TrotMania series, "Aternum Obscurum", is finally here! Under the cover of darkness, a unicorn DJ sick of underexposure and generic EDM has plotted to trap everypony at Las Pegasus's biggest dance music festival in a musical void of hypnosis, making them think the night will never end! Can you see through her smoke and lasers and dance your way to her downfall? With a brand new look and an electronic music-fueled soundtrack, TrotMania III will get everypony moving! Additionally, we have re-issued our second installment TrotMania Chrystalize in a new "Princess of the Year" edition, which includes all of its add-on updates, additional music videos, and other tweaks.
You can download it over on their website!
Thanks to @Master4414 for the heads up!