Every year around this time (冬至)DongZhi, there will be a small gathering at home whereby everyone gather to make small balls of glutinuous rice "汤圆"-"Tang Yuan". This actually symbolizes happy reunion in the family. So the night before everyone will gather to make these tiny balls normally in various colours such as White, Red/Pink, Yellow, Green which you can buy the paste from the market. I have never encounter blues ones... but there are special ones with blue, brown and purple as it's kinda mix with fruit so I guess it's special order.
Say the picture above shows the "汤圆" that I took this morning. It's made by my grandma (the mickey mouse).... Yum!