From EnMasse’s News Post:

Receive increased loot drops between Friday, January 31 (at 4 a.m. PST) and Monday, February 3 when you complete any of the following instanced dungeons:

• Bahaar’s Sanctum
• Antaroth’s Abyss (Hard)
• Ruinous Manor (Hard)
• Grotto of Lost Souls
• Red Refuge
• Velik’s Hold (7-person)
• Ravenous Gorge (3-person)

We’ve also reduced the Adventure Coin entry cost for Akalath Quarantine this weekend, but the drop rates remain the same.