Santa's workshop

Short definition from Wiktionary

Noun

1. 1
   The mythical structure, usually envisioned as located at the North Pole, where Santa Claus and a large number of capable elves work tirelessly and gladly year-round to produce all of the toys and other gifts to be delivered throughout the world on Christmas Day.
2. 2
   A fanciful replica of this structure, temporarily erected in a retail store, shopping mall, or other public venue at Christmastime as an attraction for children and parents.
3. 3
   A busy, productive large or small work environment, populated by dedicated workers.