From EnMasse’s news post:

You’ll receive increased loot drops between Friday, February 14 (at 4 a.m. PST) and Monday, February 17 when you complete any of the following instanced dungeons:

• Gossamer Vault (Hard)
• Demokron Factory (Hard)
• RK-9 Kennel (Hard)
• Velik’s Sanctuary (Hard)
• Ruinous Manor
• Lilith’s Keep
• Channelworks (3-person)
• Ghillieglade

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