1964 is a Nintendo 64 emulator for Microsoft Windows, written in C and released as free software. It is one of the oldest and most popular N64 emulators, supporting many commercial N64 games.
@Xdqwerty, Osu! Tatakae! Ouendan! is the Japanese version of the game, different settings/characters/songs but otherwise identical mechanics. I played that before I knew about Elite Beat Agents lol. Both fantastic games https://en.wikipedia.org/wiki/Osu!_Tatakae!_Ouendan