I normally call my no spend months "stick to the budget months." We are paying off debt at lightening speed right now, so there is no money for extras. We live on the bascis -- food, bills, mortgage.
I have $50 per paycheck set aside for the occasional trip to the hardware store or oil change for the car. Other than the unforseen incidentals, no other money gets spent -- and this is the hard part -- no movies, no eating out, no babysitters, no clothes, no books, no toys. Ouch.
It can hurt some days, but we are so close to being debt free that the discomfort is well worth it. And we do spend loads of time having fun. Free can be a blast. We swim, we bike, we find free stuff -- we are headed to a magic show at the library tomorrow.
So, my definition of no spend is a tight one.
Yah, really tight.
Edited to add -- I have money budgeted for gas, so I do drive when I need to. But my gas budget is tight (again with that word!) so my driving is limited.