ID:2000117
 
(See the best response by Nadrew.)
I accidentally blocked another user, and I can't see how you unblock them.

As an aside, a block feature on a forum is a stupid idea. I could see hiding notifications and PMs from someone, or by default hiding the content of their posts, but the way it currently is is very dumb
Best response
You should be able to access the list from your account page somewhere, and you can go to the person's member page and unblock them from there.
The easiest way is to click the little qt couple here -

In response to Rushnut
They're not showing up on that list, but I still can't see their posts. I also can't see them on any other list that would indicate they're banned, nor is there any indication on their page, and I can still post on their shoutbox. Nonetheless, I can't see their posts on the forums unless I log out.