I just discovered the coolest thing since sliced bread. It's this web page called Fuelly. You put all the pertinent numbers each time you fill up your gas tank and it keeps track of your mileage. Of course, being a geek, I already had a spreadsheet that does this. I signed up (for free) and put my Corolla in my "garage" anyway, which you can see here (I already put in the back information I had).
4 hours ago