We started with our elf last year!
He/She {its has changed} name is Sprinkles!
This has been the most fun tradition!
I think the whole family really have fun with it!
Not to mention, it nice at bedtime.
"remember Sprinkles if watching, and will tell Santa if you aren't behaving!"
Here is some fun stuff Sprinkles did last year:

Do you have an elf?
What's their name?
How long have you been elfing? ;)