While Electronic Arts is celebrating the fourth with double XP in Battlefield 3, Activision is taking a different approach. Starting today, all previously released DLC for Call of Duty: Modern Warfare 3 and Black Ops will be available for half-off. The deal is available on PC, PS3, and Xbox 360, and will be ongoing for a week.

That means all four Black Ops packs--First Strike, Escalation, Annihilation, and Rezurrection--will be available for $7.50 each. The two Modern Warfare 3 "content collections" are also available at a discount.

In addition, a portion of sales from the DLC promotion will be donated to Call of Duty Endowment, a non-profit organization that provides job placement and training services for veterans.