Osu! is a music game based on the concept of Elite Beat Agents; shapes pop up on the screen, and you hit them to the beat to score points. Where Stepmania is a customizable DDR game, Osu! is a customizable Elite Beat Agents game: custom themes, edit songs yourself, download as many as you want from wherever, etc. I'll talk more about Osu! in a review later; you're here for the video anyway.
If you know Elite Beat Agents (or the Japanese original, Osu! Tatakae! Ouendan), the plot basically involves the player acting as the agents, helping someone fix some scenario for themselves. This is, as the creators realized, a perfect framework for a Phoenix Wright case. Throw some Queen in the mix, and you can't lose.
I wish I could pull that off myself.