My favorite part is the guy who programmed his nose into his iPhone's fingerprint sensor. I wonder if it can really tell the difference between his nose and any other person's.
You can also use toes, and if you want to get more weird: you can also use your nipple ! Not only it can tell the difference between your and any other person's nipple, it can also tell the difference between your left and right nipples. Don't ask me how I know...
I have personally programmed my toe into my iPhone last year sometime. Purely for testing. It does work.