According to the BBC:

Boxing Day got its name when Queen Victoria was on the throne in the 1800s and has nothing to do with the sport of boxing.  The name comes from a time when the rich used to box up gifts to give to the poor.  Boxing Day was traditionally a day off for servants – a day when they received a special Christmas box from their masters.  The servants would also go home on Boxing Day to give Christmas boxes to their families.

Europe is more sensible:

The day also has religious connections and is celebrated as Saint Stephen’s Day in Ireland and the Catalonia region of Spain.  In some European countries – such as Hungary, Germany, Poland, and the Netherlands – Boxing Day is celebrated as a second Christmas Day.

However, I hope that your Christmas boxes had lots on N gauge trains (or any other scale or gauge for that matter.)  I hope it’s not like this……

And just a few pictures to inspire the modelling juices…..

Two pictures of Pacific Electric freight on the Watts line.  That four track main line is very reminiscent of an N-mod module, but I don’t think the overhead would survive the members!

An ESNG moment in Littlehampton in 1920.

Two pictures of ex-SECR E1 4-4-0’s (photographer unknown.)  One of a line of most attractive locos.

That most beautiful of locos, the LBSCR L class at Victoria in Southern days.  Note the very modern looking building in the background.

Barnham Junction in 1900.

And the Terrier ‘Whitechapel’ with a long train for such a tiny loco – again at Barnham Junction.

West Croydon.  Probably late Southern or BR days as the engine shed had gone and the carriage shed over these sidings has also been demolished and electrified.

A very modellable location – Shepperton signal box with a water tower adjacent. 

This looks uncannily like a model.  Bricklayers Arms in 1968.  Edit – thanks to Dave C, this is actually the South London line crossing the Old Kent Road.  I’ve added the NLS map segment below, and the ambulance station next to the railway is easily seen.  Still, it’s a great photo…..

And finally, how Christmas trees travelled in the olden days.