Food:
Black Beans -- cook a large batch of dried black beans in a crock pot (or on the stove). After beans cool, put them into glass jars and freeze. When needed, thaw in the fridge or in the microwave. Cheaper, healthier, and easy!
Veggie bits -- collect wilted veggies and herbs, end of carrots, celery, and onions, in an airtight glass container in the freezer. When you have a chicken carcas, cook it with the veggie bits for a delicious, home-made chicken stock.
Rice or quinoa leftovers -- if not enough is left for a meal, save and add to any soup.
In the kitchen:
Freeze cooked beans, soups, veggies, home-made pasta sauce, or anything else in glass jars.
Around the house:
Paper -- collect all paper that has been used on one side. Cut into halves or quarters and use for to-do or shopping lists, notes to your spouse, or create cool recycled scrap paper notebooks