I'm on a Mac and I tried to replicate the problem with a few browsers (Firefox, Safari, Navigator, Flock, OmniWeb, Camino and Shiira) without signing on. Not once did I have any problem either loading the site or any particular thread.
For those on Macs, I would suggest the following:
1) Empty browser cache
2) Restart on Mac OS X disc (hold down the letter "C" while it is restarting.
3) Run Disk Utility—both repair disk and repair permissions
4) Restart and see if it still happens
Good luck.