You can be an entrance elf, a water cooler elf, a bridge elf, train elf, maze elf, island elf, magic window elf, usher elf, cash register elf or exit elf.

NPR: Crumpet the Elf Reads from Santaland Diaries

Some double as games, such as an igloo-shaped one that is actually a maze with a ball and a "magic box" that is also a flip puzzle.

FORBES: Magazine Article