I have not, but am curious.
I've read that if you are going to eat it raw you should freeze it for at least 14 days, but even then it might not be totally pathogen-free.
It's said that some hunters will eat the fresh liver of the animal that they just killed, while it's still warm and, ahem, throbbing.
I also know that Japan banned service of raw beef liver in restaurants as of July this year.
Anyway, curious if there are any raw liver afficianados out there.