I came across this today. I didn't taste it, because, well...it just looked unnatural to me. After Googling 'blue rice' I discovered that apparently it's coloured with the flower Morning Glory. Even if I knew that it wasn't riddled with blue dye, I still wasn't sure what to do with it next. The rice platter was surrounded by bowls of toppings/condiments...so I guess you just flavour it to your own liking?
Snap's other blog Chiang Mai Thai