Good for you! This means that you'll always be able to live within your means! Personally, I'd put away the money, as you may find a reason to spend it later (bigger house, education for the kids, etc.). If you're looking for a reward for yourself, maybe find a way to translate that money into time, buying services for things that you don't like doing. If you're just looking to burn away some of that cash, perhaps consider donating it to a cause where you think the money will be put to good use.
I understand your situation. I'm living on a grad student stipend, and while I don't feel flush with cash, there isn't much right now that I feel I really want and can't have, except maybe a house.