Signing up to the forums is required to gain access to its contents and the raid calendar. You have to register using the name of your main character in the guild, otherwise you will not have access to the raid calendar.

Forum Access
To sign up for forum access click on the Register link at the top of the page and follow the instructions. When you are done registering contact an officer to activate your account.

Calendar Access
Members of UD automatically get access to the Raid Calendar if and only if they have registered using the name of their main character and their account has been activated.