This is pretty much my favorite "forum game". We start with one word, and then the next poster says the first word that pops in their head for the word you posted, and then the next person posts he first word to come to mind when they see that person's response. So like...

Person one: Raining
Person two: Cats
Person three: scratch
Person four: lottery
... and so on.

We keep going until we end up going in circles *or* someone posts something so obscure or such a deep inside joke that no one can come up with a word for 48 hours... then you start over with a new first word.

I shall go furst... with CORGI