BioWare put out numerous single and multiplayer DLC's, and a countless amount of multiplayer "N7 Bounty weekends." With the final DLC for the game now available, the company is set to bid the game adieu with it's largest and longest multiplayer event to date.
Here's the mission briefing direct from Admiral Steven Hackett:
"We are coordinating the largest-scale attack in the brief history of this war. N7 unit actions will pave the way for resistance and conventional forces trying to retake the population centers of our homeworlds. There is no retreat. When an objective is finished or a target destroyed, you will immediately focus on the next. Our assets will provide cover to network ships that will update your targets in real-time. Rally points are at your disposal in the event that all space assets meet with catastrophic casualties. From there, you will fight as your CO sees fit or until further orders arrive.
I cannot fully express my deep respect for all of you, the sapients of the Milky Way who serve together under our banner. When future generations look back on this war, they will see the courage and commitment it takes to change the fate of a galaxy. It has been a hard road, but at last: the end is in sight.
Finish it."
Operation Lodestar will go from Wednesday to March 10th. Apart from the length of the operation, it differs from past N7 weekends in that it offers rewards on three different tiers.
The BioWare Blog offers the skinny. Participate at all, and the first tier reward (commendation pack) is yours. Extracting against all four enemy factions on Silver difficulty or higher earns the second tier reward: a banner, and bonus commendation pack. Do the same on the highest difficulty, platinum, you take home the biggie: a third commendation pack.
Best of luck.