A rar-full of dicks is a file, usually a .zip or .rar archive, deliberately named something to entice people into downloading it, but is usually something completely different, normally something most people would consider unpleasant or embarrassing, such as pictures of male genitalia.
Tommy thought he downloaded a .rar containing the full version Assassin's Creed, but instead it was hundreds of pictures of gay porn. Tommy ended up getting a rar-full of dicks.
A message board that is still online, but is practically deserted, save for a small group of people who still visit it. Normally there are large amounts of broken links, and any topics not on the front page are a few years old.
Armageddon Games Forums is a ghost forum, it's still around but it's slowly shrinking away.