Got these (decorative light string on the rails + Solar Powered Fence Post Cap Lights Deck) from amazon, and they really work! 
13-Dec-2012 20:23, Panasonic DMC-GF1, 1.7, 20.0mm, 0.125 sec, ISO 400
Adding Some Green II Solar Powered Lights 太陽能燈
Tag: solar powered lights