The story
For most families this is the larger half of the festival. The reunion dinner is the meal everybody travels for, and an empty chair at it is the thing the whole journey exists to prevent.
The food is chosen for what its name sounds like: fish (yú) for surplus, because there is a phrase about having a surplus every year, and it is served last and not finished. Dumplings in the north are shaped like old ingots; nian gao in the south is a homophone for a higher year.
The house is cleaned before dusk and not after — sweeping on the day itself sweeps the arriving luck back out of the door.