Found a neat site today. It is fuelly.com. This site helps to track miles per gallon(mpg) and cost for running your automobile. You can log information to the site via the website, mobile site, or SMS(if located in US,UK, or Canada). Just started using today but it looks really cool. Data can be exported from the site so you devs might be able to do really cool things. One guy has already created some PHP classes to gather data from the site. You can find his work here

-codedragon