How about a "what they were really saying" contest
Each poster is to reply to a recent poster above them, translating what they said to better define what they think they were probably
really getting at.
like say you start it off by giving a random statement (probably about a Volt, but for this example...) like, I dont know, maybe:
"I love me some Monday Night Football"
The next poster will follow yours with a quote and translation of what you are actually getting at like maybe
"Drinking makes everything better!"
where the next poster might reply with:
"If I keep serving beer, maybe people will come to my house!"
and so on... (bad example, but you get the idea)
Will mean that there isn't a specific continual topic, but people will also be forced to interact with each other quite a bit and I imagine it can lead to some extremely amusing replies/translations. Probably an amusing after-the-fact reading
thread
Maybe limit it to one entry per 5hours or something, until "x" amount of posts are tallied, and you can score it however you like.