I posted a thread in General Hardware about the Voodoo5, about a month before it was released, and that got something like 250 replies. I also started some sort of thread about Intel and AMD which got over 200 replies I think. My off topic threads suck and I very rarely ever start any. I seem to remember posting one about ghosts a few months back which got a reasonable (over 50) number of replies...
No match for the 'I'll say one word and you say the next' threads though