Activision Blizzard announced Thursday that it will publish the third map pack for Call of Duty: Black Ops on Xbox Live at the end of this month.

But what Activision Blizzard did not announce was when — or if — the map pack would come to players on Sony’s online gaming network, the PlayStation Network (PSN). That could be because the PSN experienced an outage after hackers were able to break into the network and steal sensitive information about more than 77 million PSN users. Sony was forced to take the PSN offline while Xbox Live remained online and flourished during Sony’s downtime.

Call of Duty Black Ops is one of the best-selling video games of all time, with sales of more than $1 billion since the launch in November. Activision Blizzard previously launched its First Strike map pack in February. Itlaunched its most recent map pack, Escalation, in May.

The map packs, which are add-ons for the game that feature new levels for multiplayer matches, are a lucrative business for Activision Blizzard. Both previous map packs are the highest-selling add-ons on Xbox Live, according to Microsoft.

The third map pack, called Annihilation, will give Call of Duty: Black Ops players four new maps: Hangar 18 (one of the most famous buildings in Area 51) Drive-In, Silo and Hazard. The new maps will take gamers to exotic locations like Shangri-La, where they will have to fend off hordes of zombies and avoid traps in the legendary location that’s supposed to be an earthly paradise.

Activision Blizzard has said customers have played the Black Ops game online for more than 2 billion hours since its launch in November. You can expect more Call of Duty fans to log into the Xbox Live service starting today, since they won’t be able to play on the PSN or on Sony Online Entertainment’s PC online games, which were shut down today pending an intrusion investigation.

Activision Blizzard said some time ago that it had sold more than 20 million Call of Duty map packs, generating more than $300 million in sales. So it’s clear that map packs are a big business, and video game publishers may want to avoid publishing rival games on May 3, since gamers will be a little busy. You can catch a full video of the trailer for the map pack below. Activision Blizzard’s first map pack, First Strike, sold more than 1.4 million copies on Xbox Live on its first day of sales.