Ground beef is one of the most versatile things around, and easy to do a variety of simple meals with (ground chicken, turkey, etc. as well).
Brown ground beef, breaking it up as it browns, and add:
Canned tomatoes, potatoes, carrots, onions, any other vegetables, for hamburger stew.
Canned tomatoes, rice, bell pepper, onion, dash of Tabasco, for Spanish rice.
Cream of mushroom soup, mushrooms, sour cream. Serve on noodles for hamburger stroganoff, or on mashed or baked potatoes, or on rice.
BBQ sauce--serve on toasted buns.
The possibilities are practically endless.