Usually Tuesday morning Pacific Time, however the servers can be taken down at other times as well for emergency or short notice maintenance if there are issues. You can read the posted Maint times here on the Service Status Forum http://us.battle.net/d3/en/forum/5394512/
Threats of violence. We take these seriously and will alert the proper authorities.
Posts containing personal information about other players. This includes physical addresses, e-mail addresses, phone numbers, and inappropriate photos and/or videos.
Harassing or discriminatory language. This will not be tolerated.