We buy hamburger meat in bulk (5-10 lbs.) when its on sale. I cook it in a large pot all at once. Sometimes I add a couple of chopped onions and some seasonings like garlic and salt. When it is all cooked and cooled-- we divide it up in 2 cup containers and freeze.
One of our favorite crock pot recipes (Beef and Lentils) uses one of these containers of cooked hamburger meat or you can use leftover shredded meat like chicken or whatever you have.

5 cups water
1 lb. package lentils - rinsed
1 tsp salt
1 lb. or two cups ground beef browned
1/2 cup ketchup
1/4 cup molasses
1/2 tsp Worcestershire sauce
1 small onion finely chopped

Cover cook on low 6-8 hours.<SPAN class="046380200-07102007"> (Crockpot)