Stock is definitely the way to go to get the most use out of the bones. I do it a little different every time, but the basics are to roast them in the oven for a while, and then you boil them (for as long as your patience can last), and strain the results. Google stock recipes, and don't be afraid to use the beef stock recipes - the process is all the same in the end.
I'll do this with all the leg bones - the spine and skull can even be used, but you're best to skip them if you are in a possible CWD area.
The exception is the shanks - Steven Rinella has an awesome
Osso Bucco recipe that I have yet been able to improve.