The Underpants Project
You can view source to see what they're using to generate the fingerprint: screenSize, devicePixelRatio, timezone, mimeTypes, plugins, httpAcceptHeaders, fonts. It's interesting that these are enough to generate a moderately unique fingerprint. I'm sure my fonts list is unique, so that's probably enough to ID me right there. However, not every computer I use has the same fonts installed, nor the same screen dimensions. This won't track me as I go from my desktop to mobile device.