YOu can use mine if you want. Here's a screenshot of it.
http://home.comcast.net/~kelvrick/mpg.jpg
First column is date of filup with miles traveled since last. Then gallons purchased, then calculated mpg, then the mpg displayed on my trip computer. The next collumn has little notes, like drive to tahoe, back from tahoe, oil change, tire rotation and such.
EDIT: I'll post it when I get home if you want it. I never came up with one from maintenance related things though, since subaru has my.subaru.com where you can track all of that. I guess I should come up with one for the GF and her corolla though.