Milan design group Carnovsky created what is probably the most psychedelic fun wallpaper you'll ever see today (without having to ingest anything):

Three overlapping and primary-colored patterns are placed on the wallpaper panels and, in normal light, create some major visual discord. But here’s where the magic happens: Shine a red, green, or blue light on the walls, and different patterns are isolated and made visible. Each colored light reveals its own set of images.

Link | Larger photos at Carnovsky's website