I know that I could, and my wife would also be willing to do so. Two years ago we went through a summer of significantly reduced income, as neither of us had summer teaching gigs and freelance editing and writing was a bit soft for me. We dried clothes on the clothesline, turned off the A/C units, forced ourselves to use up the freezer and pantry food, rode bikes more, and managed to make it through a three-month income squeeze without tapping into our savings.
I think the experience made me even more thrifty in the long run. I currently limit myself to one fast food lunch a week, brown-bagging or opportunistically "scavenging" at events for a free meal the other days (someone is always offering pizza or subs on campus to attract an audience, from the College Republicans to Save the Ottawa River to, I dunno, Free the Starving Darfur Whales). Heck, if the CPUSA offered pizza and wings for lunch, I'd wave the hammer and sickle for free eats any time.
We also installed a peninsula fireplace this winter, which cut our heating bill about $30 a month. It heats the rooms we use most often, and its close location to the furnace thermostat means our furnace runs a lot less. It mostly runs when we are in bed at night.
I also make it a point to never carry cash or a credit card when I am on trips within a few miles of home. This way I cannot give in to urges for a quick hamburger, a car wash, or any other unnecessary expense.