My buddies and I were a little disappointed that there was no N7 Day challenge this year, so we made our own. Sorry about any errors in lore: ;-)
N7 Day Challenge
Saturday 22 November
Operation Cleanup
Time to commemorate N7 Day in 2014! You may want to make sure you have a couple of level 20 characters for this! 
After Shepard destroyed all the mass relays, surviving Reapers, Collectors, Geth and Cerberus have forces running wild. Without a central uniting leadership, these enemies have splintered into minor factions dominating various far reaches of space.
Challenge 1:
Supplies are low in the Attican Traverse; send in 4 of your best soldiers to Pragia and use the little equipment there is to protect the colonists there (Pistol Round):
Complete any enemy on any map with only pistols. No grenades, no powers, no biotics.
Challenge 2:
Thane has left 4 children behind on Earth. They stumble upon a Collector Hive in Vancouver. Take your all Drell team to fight the Silver Collectors in Firebase Vancouver.
Challenge 3:
The Geth want revenge:
A small splinter group of Geth have hit the migrant fleet. Take control of the Quarian forces to rid their fleet of this scourge. Silver game vs Geth in Firebase Reactor, using only Quarian players. Will the Quarians squash their creations, or will the Geth finally overcome their creators?
Challenge 4:
Thessia Revelations:
The Asari homeworld, Thessia, has been attacked by numerous Cerberus splinter groups. Take an all Asari team to fight the Gold Cerberus agents on the Asari map Firebase Goddess.
Challenge 5:
Some of the most powerful Reaper forces have finally reached Arvuna, the moon of Dranen. Go in and destroy them, using any units and force necessary:
Platinum Round:
Complete any enemy on Platinum on Firebase Hydra.
Suggestions welcome!