Yes, I know, I've already told you all about making simple chicken stock, and the premise here, it isn't all that different. So take this as a reminder to take advantage of the things you would normally throw away!
When I cooked up 8 pounds of beef ribs last weekend, I was already thinking about all of those big, flavorful, Flintstones-esque bones. As people were insisting to help clear the table, I instructed everyone to just toss their bones back in my big stockpot, so they would be ready. After our guests left, at close to two in the morning, so I'm aware this makes me insane, I tossed the lemon tops I used for the dessert garnish in with the ribs; a few handfuls of baby carrots; some celery stalks, broken in half; a fair bit of salt and pepper; two medium onions, very roughly chopped; a few crush cloves of garlic; and a handful of each of the fresh herbs I had on hand--parsely, rosemary, thyme, and tarragon.
I covered this delightful mishmash with cold water, plopped a lid on it, and set the temperature on low. My idea was, since I planned to be home all weekend, to simmer the beef stock for two days to extract maximum flavor from the bones.
Guess what? After a slow simmer and a thorough straining, it worked! I now have a whopping 10 cups of homemade beef stock to work with. It is so much, in fact, that I'm thinking about reducing half of it into demi-glace. But we'll just see about that. After making your stock, remember to let it cool then skim off any fat before freezing. Have fun!