I've only ever experienced 240ac @ 50hz, and I got thrown off each time (luckily). I felt the last one go right through my chest, thought my heart was going to come out of my chest for a while... that was 20 years ago (when I was about 15), haven't been shocked since...
Apparently, if the only live/not live test instrument you have available is yourself, it's best to touch the object in question with the back of your hand: That way, if it is live, when the muscles contract you won't end up with a death-grip on the live item...