One of the basic concepts I adhere to in the kitchen is the idea of one base item being made into many things. Freezer meatballs making not only spaghetti, but appetizers and sandwiches. Pre-cooked ground beef for tacos, sloppy joes, meat sauce, pizza topping, etc. Chunked cooked chicken for stir fry, chow mein, ala King, chicken salad.
The trick is to freeze the base ingredient in portions that you commonly use. 2 Cups of pre-cooked ground beef is equal to one pound of raw hamburger, browned. Once you know that, it's easy to substitute into any recipe that calls for browned ground beef.
Some people may ask why you would brown it and freeze it... why not just freeze it raw? Well, there are several reasons why it's more convenient.
One thing I am always concious of here in Texas is that we have power outages during hurricane season. Not always for long, although the week after hurricane Ike was horrific, but often enough and long enough to be a concern. It was handy that the meat was pre-cooked, so all I had to do to make a stew was dump everything in a pot over a charcoal grill.
It also saves time and heat in the kitchen. I often put it into the meal in a still half-frozen state before cooking it up the rest of the way. Instead of dirtying five pans, browning the meat at each individual meal, I've only dirtied one pot pre-browning it for the freezer. Not to mention that thawing the raw meat overnight in the fridge or in the microwave is a messy, potentially hazardous proposition. I would much rather have a pre-cooked package of meat thawing in my fridge than a raw one.