Market Camping
This can be relatively fun after you have a good stock to start with. All you have to do is go to the auction house and sell some things at the best price you can get for them to start of with. Then look for a high selling item at the best price that they have. Buy this in bulk. After you have all you want sell at the best price you can get and keep continuing this until you're done. If your lucky enough you can sell the gold for real money.