The VidiMasher 3000 is a rear-projected, infrared-based fake touchscreen. A laptop screen is projected on a translucent screen, and mouse movements and clicks are made with a special infrared light pen. Standard Nintendo Wii controllers are mounted near the projector which bridge the infrared pen actions to mouse actions on the laptop. As functional as any standard mouse (at least), I created the VidiMasher specifically to work as a music controller to perform (rather than DJ) live mashup music (aka audio collage) in an improvised manner but with a mix and tempo polished enough for a club crowd. It also gives the audience an opportunity to watch how the music and musician work, giving literal transparency in the musician’s actions and skill. It also looks much better than a glowing Apple logo for an hour.
VidiMasher 3000 demo video: