There are things similar to this but i thought it might be fun.

I'll type a sentence, and the next poster has to say a sentence related to one said last. The sentences first letter has to be the last letter of the sentence above the poster.
Example:
Aliens are taking over the world!
<next poster>
Darn!
<next poster>
No way!
<next poster>
Yeah, they've just blown up the white house!
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Shut up!