I'm part of the All-American Reject's message boards which is a ubbthread and recently someone joined the boards and they made their text centered. Are there any codes that aren't used a lot that I don't know about?

There are quite a few ubbcodes, such as [center]; most of these are covered in the markup panel on the "full reply" page.

uhhh....wheres that at?

Click the "Reply" button at the bottom of each post.

To answer the question in the other topic, the version site is using is UBB.threads™ 6.3 and UBB code is enabled so it must be a specific code that is being attempted that is designed only to work in later versions...spoiler tag for example, which is presently a modification.

Yes, if the old site is running 6.3, then codes for 7.0 (such as the text alignment codes) won't work for it as they where added later.

Another good example is the Spoiler tag, which will be added in 7.2; it will not work with prior versions without being added into the coding by the owner of the board as a modification (should one even exist for that version).

Also, 6.3 is fairly old and insecure, your admin should consider upgrading to 6.5.5 at minimum.