One of my favorite health tips is to replace the ground beef or vegetarian crumbles in any recipe with red lentils. Red lentils are mild in flavor and quick to cook up. They're packed with fiber, protein, iron, and all sorts of other good things for you. Lentils have been shown to be good for your heart.
I've been a vegetarian for many years, and my solution for recipes requiring ground beef was originally to use "vegetarian ground beef." And while that's not the worst thing in the world for you, I prefer red lentils because they are cheaper and a whole food.
The other night, I made a simple red lentil chili with canned tomatoes and chiles. Basic but delicious. Red lentils also make great sloppy joes - just cook them up and put them in your favorite sloppy joe recipe.