I know! I know! Wordwind, purdy please, pick me!

I think.

LED Festoon Bulbs are housed in lens that uses sun's UV rays to produce glow, even when lamps are not powered up. Lambertian lighting pattern provides even distribution of light. With lamps lasting up to 100,000 hours, bulbs can replace incandescent bulbs in indoor and outdoor applications. - Online Auto Dictionary

Ah ha! An excellent application of this form of lighting would be a string of colored lights to decorate a Christmas Tree.

(Now don't you think well of me?)

http://www.oldchristmaslights.com/interesting_facts.htm