During the winter, I tend to spend a good part of my Saturdays in the kitchen. If I'm not baking bread and enjoying the fabulous aromas from that, then I've usually got a pot of vegetable stock simmering away on the stove.
Vegetable stock has got to be one of the easiest things to make, mainly because a recipe for it is simply a guideline and can be tweaked or altered at whim. (And the process for making it intertwines well with doing laundry!)
Take a big pot. I've got a good sturdy Dutch oven that works well for me... you don't need to splurge on a big stock pot.
Peel and chop an onion, some garlic, and lots of vegetables (I usually use potato, sweet potato, carrots, and celery... do NOT use broccoli, cauliflower, cabbage, tomatoes, or bell pepper unless you want a stinking mess). Throw them all into the pot. Don't put too much effort into it, just get them clean and chopped up enough to let the nutrients leach out.
Add herbs: parsley, bay leaves, and chives are basics, but if you know what you'll use the stock in and want to give it extra flavor to coordinate, you can add basil, oregano, rosemary, sage, dill, ginger... whatever! (Just not all of them at once.) Fresh or dried, doesn't matter. Toss in some peppercorns and a few allspice berries, fill with water. Bring to a boil, then simmer for an hour or so.
Strain the stock into quart glass jars and let cool, first on the counter and then in the refrigerator. (Don't try to freeze a glass jar of stock until the next day... the stock takes a long time to cool, and if you put it into the freezer right away, you'll find a frozen, shattered jar and unusable stock. Not pretty. Trust me.)
The vegetables that are left over make really good compost... and in the winter, tossing those steaming soft bits and bobs onto the compost heap is such a nice treat... you can feel it starting to break down the other scraps right away.
The end result of this whole process is a golden liquid that adds flavor to soups and stews and other recipes that would just use water (like rice dishes, sauces, etc.). You can also use it just for a broth, though you might want to saute some scallions or garlic and add some salt to enhance the flavor.
And your house smells great for the whole day.
Saturday I got three full quarts of stock out of the pot, and I promptly put one quart back into the pot later that evening while making corn chowder (with unsweetened soy milk... I love this stuff!). I'm not entirely satisfied with the chowder... it's a little bland for me... so I may experiment some more with it. But I've still got two more quarts of stock to play with, and though one may end up in the freezer tonight, I have an idea for the other one later this week.
Now, to make more crackers to go with the soup...