Yes, you saw it with rats, turkeys and reindeers; fact it, you're eventually going to buy one of these, so why not snowmen and snowballs? NO JOKES PLEASE!
Okay, the concept is simple: take the snowballs numbered from 1 - 6 and arrange them on the three sides so that each side adds up to 9. Rearrange them and they add up to 10. Do it again, and they add up to 11. Then do it one more time and they add up to 12. Record your results and see for the patterns that emerge in the corner numbers.
Want to make it more interesting? Do it with the digits 5 - 10 instead and see what happens; what about odd numbers? Even numbers? Multiples of 5? All sorts of interesting patterns emerge.
This activity includes extensive explanations on how you can differentiate it for your students who need a real challenge, as well as simplify it so that even your struggling students will enjoy it.