Here's an idea:Forum Games (Anyone watch Idea Channel?)
I personally think that every forum should have a topic/subtopic/whatever-ever-it-would-be-called where users can play fun games based on forum mechanics.(No I am not talking about rp's. Duh.)
If you have not been lucky enough to be on a forum that has a Forum Games let me explain it to you by lists of games to be found there:
-Corrupt a wish.
User posts a wish, the next user posts that there wish is granted but, something g goes wrong. Then user #2 posts their own wish.
-Question Game
A user posts a question, then the next user post the answer to the question as a question.
Belt Game
User Posts a word, next user posts a word that starts with the last letter of the previous word.
That concludes my pitch, any questions?

That's what ends up in Spam generally, that and random topics. I'll admit there aren't as many "game" threads as there used to be but that's where you'll find them and that's where they go. So we have a section for what you're after, you just may need to sift through some random topics before you find the threads you've given for examples.

Okay, Thank You.