Kismet's Dungeons & Dragons pretty much feels like just one GM's (ok....DM's) personal website being used to keep track of campaign-specific details. I originally stumbled across this site years ago when I was looking for some information on how to value slaves for my campaign. Personally I found Kismet's Guide to Slave Costs quite useful.
There are also pages with
Kismet's Dungeons & Dragons has a lot of good info you might find useful for your current, or future campaign.