Weekly quest

Weekly quests, or weeklies, are repeatable quests that can be acquired and completed once/twice per week. First introduced with patch 3.1.2 in the combat zone Wintergrasp, they tend to have significantly better rewards than other repeatable quests.

Restrictions
The new weekly quest becomes available—at the start of the day—every Tuesday for US servers and Wednesday for EU servers, after the weekly server maintenance.

A special case were the Wintergrasp quests, which also reset every five days, in addition to the weekly reset. This is no longer the case as of patch 3.3.2.

Weekly PvP quests
Currently the only zone to have PvP weeklies is Wintergrasp.

Dalaran
Weekly raid quests are now available from in Dalaran. Every Tuesday at 3 AM the Council of Six will choose a different strategic target that must die from either: The Obsidian Sanctum, Naxxramas, The Eye of Eternity, Ulduar, Trial of the Crusader, or Icecrown Citadel.

Notably the Dalaran weekly raid quests still award 138 Justice Points to groups with players level 81 or higher (even though the group does not gain Justice Points when downing a Wrath boss).

Weekly Icecrown quests
One of the following quests will be randomly selected during each Icecrown Citadel raid ID. The quests involve completing extra objectives during the instance, often by doing something different during a boss fight.