From EnMasse’s news post:

Receive increased loot drops between Friday, January 24 (at 4 a.m. PST) and Monday, January 27 when you complete any of the following instanced dungeons:

• Gossamer Vault (Hard)
• Grotto of Lost Souls (Hard)
• Demokron Factory
• Macellarius Catacombs
• Shadow Sanguinary
• Channelworks (3-person)

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