Seen a few people ask about what todays "silent" patch was for, looks like they released the notes a little late. If you missed it on your patcher (werent available when they released the patch), here they are. Nothing big or ground breaking, but they fixed that 1337 nightfall exploit:
World of Warcraft Fast Patch 5.1.0A Notes - World of Warcraft
Bug Fixes
Pet Battle Abilities that use a shoot or missile animation will now properly display their visual effect.
Disabling Loss of Control in the Interface menu will now also disable the red cooldown swipes on the action bar in addition to the notification in the center of the screen. Loss of Control Alerts can be disabled in the Game Menu by going to Interface > Combat > and un-checking Loss of Control Alerts.
When Loss of Control Alerts are enabled, the red cooldown swipes will not be displayed for abilities that were already on cooldown and in situations where that cooldown will last longer than the loss of control.
Night will now fall at the proper time on all realms.
Objective icons in Scenarios will no longer incorrectly persist until the Scenario is complete.
Fixed an issue that could cause crashes during Pet Battles.
Mac
Fixed an issue that could cause a crash to occur during in-game cinematics in OSX v.10.6