Backchatter – a game about Twitter trendspotting

In my Guide to 140 Learning: How to use Twitter, Facebook and Buzz for Social Learning one of my pages is  called "Using the backchannel at an event.  "This page looks at the use of the backchannel from the perspectiive of both the audience and the presenter.

Whilst I was researching this topic I came across a Twitter game played at conferences –
Backchatter
– where you pick words that you think people will tweet about,
and then you get points when those words are used in
tweets about the conference
.

Does anyone know of any similar or other "backchannel games"?