 The FDA has approved oxaliplatin to be given to people through their veins to treat advanced colorectal cancer. Giving oxaliplatin directly into the abdomen in this study is experimental and is not approved by the FDA. This study will give the standard chemotherapy FOLFIRI through the veins and oxaliplatin directly into the abdomen. This is the first time intraperitoneal oxaliplatin is being given in combination with FOLFIRI. 