Bungie is treating us to two weekends of double experience and promoting two fresh Halo 3 game-types.
Beginning this evening at 8pm GMT and ending at the same time on Monday, you will be able to enjoy popular mod Grifball in an unranked "social playlist".
Grifball is similar to rugby; two teams of four grab a ball from the middle of the pitch and try to run it into the opposing goal. There's no passing allowed and everyone will have gravity hammers and energy swords to stop you scoring.
Bungie has altered the rules a bit, although it assures us the core of the original is still there. The developer is offering tournament prizes too. Charge over to the official Grifball site to find out how to play.
Then, on 20th March at 8pm GMT, you will see the return of Team SWAT from Halo 2. Once again, this is unranked and earns you double experience. You'll be battling with no shields and no radar but your health will be increased. This will end on 23rd March at 8pm GMT.
Bungie has also made a few alterations to the Heroic DLC hopper, which has been split into DLC Slayer (4v4) and DLC Objective (6v6).
Each will have a number of game-type variations: Team Snipers, Team Rockets, Team BRs, Team Duel and Team Duals for Slayer; and Multi Flag CTF, Multi Flag BR, One Flag, Assault, Neutral Bomb Assault and Team King for Objective.
Matchmaking and various maps have been fiddled with, too.
The biggest alteration is reducing the size of a "Large Party" in Ranked Big Team Battles from seven or more down to six or more. "Mixed Skill" parties - those with a level spread of 10 or more between best and worst - can now face off against non-mixed groups.
This should decrease waiting times when searching for games. But Bungie will be keeping a close eye on it going forward to ensure it doesn't descend into organised groups routinely steam-rolling rabbles of solo players.
Call of Duty 4 has pushed Halo 3 down to second place in the Live activity charts recently, but Bungie will fight back.
"We have a lot of awesome new content coming up We're not walking away from Halo 3," Bungie's community lead Brian Jarrard told Eurogamer at GDC.