In a blog I have, Trishinomaha mentioned how she recently made a purchase from Fantes.com and I realized thats where I saw them.
Now this is a looooong page top to bottom, but if you scroll down towards tyhe bottom you will start coming across the conversion tools.
You will find Temperature from F - C and back
There is a weight conversion tool, a metric and english liquid volume converter, and a variety of other tools.
One labled "Body Mass Index (that one Im staying away from)
This has helped me convert recipes from ounces over to grams. Very simple, easy to use.