A while ago I decided I wanted a form of dim lighting for at night time, I went for LED lights run off 12 volts. After I installed some Blue LEDs, I figured it would look cool if I used several LEDs and made multicoloured shadows.. This is the result.
The effect is achieved using coloured straw-hat LEDs in a string (Red, Green, Blue and why not UV) around 15cm apart, facing a parallel-ish direction. When the shadows intersect you get this cool effect 😛
In order to get the colour to come out on camera I used a decent Canon on RAW mode.