The Dark Room Sex Game is an erotic rhythm game without any visuals, played only by audio and haptic cues using the Nintendo Wiimote controller. A phallic object which also has vibration, the Wiimote is the perfect tool for this game. Players seem to thrust it around, looking not to visuals which are the typical signifiers of Nintendo game play, but instead listening for aural reinforcement. Like Ooohs and Aahhhs. The players work to find a mutual rhythm with their partners and gradually speed up until orgasm.
The team of students at the IT University of Copenhagen who developed the game explain their concept:

Our idea was that a sex game would in fact be even more erotic if one stripped away all visuals and forced players to use their imaginations. Our hope was to use a combination of humor and embarrassment to make players uncomfortable, yet strangely satisfied. One could view the game as a commentary on the dull fixation on visuals in the spheres of sex and also videogames. Or, you can just view it as a cool party game.

Have a listen: