Grab a level 80 character and harvest the heck out of the Bonemire zone in point from Tenebrous Tangle. Not only is it a great area for tier 7 harvest stuff (or maybe 6), but the amount of shiny collectibles in immense.
Now I know it's not the best way to make mad money. It's rather redundant and maybe not for everyone. But there is something fun for me about generating revenue from nothing.
What do you do for money on your server?