These are a new form of decorative external lighting.
The most common form of this outdoor lighting is coloured discharge tubes. These works similar to the orange sodium SON type lighting used to illuminate pubs, car parks and monuments etc. The conventional HID (High Intensity Discharge) versions of the orange SON more commonly give the familiar blue-white light, however they are now available in coloured versions Including pink, blue, purple - UV, red, green, orange etc.
Simply use a conventional 70W / 150W HID floodlight fitting which is fitted with ballest and control gear, then simply replace the conventional tube with a coloured version.
This is the more popular way of lighting up a building in fluorescent pink or UV Purple

and often seen lighting up pub gardens etc. A fitting will cost around £50 and the tube between £29 and £60 depending on whether you have a 70W or 150W version. Not too expensive, considering you'll get around 6000 hours from the lamp
These new coloured discharge lamps are available from
HERE