I have looked everywhere for a good recipe, and they all call for coffee. My grandmother made great red eye gravy, and definitely didn't put coffee in it. SJ's mother's observation got me thinking, and I remember my grandmother always started it with a roux for the brown color. I got out her book, and here's what I found--
After baking a ham, scrape drippings into skillet and brown up. Add 1/2 cup cold water and bring to a boil. Cook until it turns red.
Let me translate that from Martha Harris to Martha Stewart for you --
Remove pan drippings from a baked ham to metal bowl, and place the bowl in an ice bath or the freezer. Once the fat has congealed, remove it from the bowl and discard. In a heavy skillet over medium heat, melt 3 Tbsp butter (she would have used the fat, she was old school). Sprinkle 3 Tbsp flour over the butter and stir to prevent lumps. Cook until brown and nutty, and a spatula pulled through the middle leaves a path for 2 or 3 seconds. Pour in pan juices a very little at a time to keep the roux from getting lumpy. Gradually add all the juices and 1/2 cup water and bring the mixture to a boil over medium-high heat. Once it reaches a boil, reduce the heat to medium low and continue to cook for 10 minutes or so. My grandmother would chop up a little piece of ham and add that to the gravy before serving.