Thin Veneer is good, but I'd recommened reading it on
http://www.fanfiction.net/~albertg
But seriously avoid any of the "worst fanfic" threads, there like a minefield in Miss World contest. Great fun most of the time, until with one wrong move it all goes horribly wrong.
As for the rest, if you want to see people carefully watching films/TV shows to work out theoretical weapon yields then VS debates is worth a look. It is seriously worrying, yeah I like sci-fi and having stupid discussions. But then I also like going to the pub and going out on the cop, something this lot seemingly don't have time for.
Having said that this still makes me laugh:
http://forum.spacebattles.com/showthread.php?t=44822
It was also where I was first introduced to this gem:
http://ocean.otr.usm.edu/~nglenn/kirkfu.html