Don't drive for one day.
So, ya think you can do it? I know, it may seem really hard, but just for one day this week, try to give up driving your car. It'll be easier than you think, I promise.
I, myself, am currently striving to be completely car-free, and, honestly, if my two jobs weren't both more than 15 miles away, I'd have done it years ago, but I'm still trying to get used to the 1.5 hour one-way bus commute.
However, this Wednesday, September 22nd, is World Carfree Day, so what better time to try and loosen your dependence upon the gas-guzzler in your driveway or garage? Ride a bike, ride the bus, skip along the sidewalk, or call in sick and don't go to work at all! Either way, try and go without driving on Wednesday. See how you feel, and maybe you'll be able to make it more than an occasional experiment! Good luck!