I have too much respect for our 240 V supply, so the closest I've usually been is when working on customer's unearthed equipment, signalled by the buzz in the fingertips.
Many years ago I found out how to empty a room (and discover who your REAL workmates were). I'd set up a small test lab, and had to teach them how to use the kit. The last test was 600 V and the calibrator hadn't de-energised after the last test. I picked up the unit under test, and discovered it still had 600 V applied. Needless to say, it was quickly thrown down, landed on my lap, and got booted across the room. When I looked up, I was alone, and all my (former) colleagues were watching from a window in the next room
The real stuff is not to be taken lightly. I learned one of my former workmates (in his early 20's) was found collapsed beside an RF drying machine he had been working on, It was basically a microwave that dried the adhesive binding of diaries. The investigation found two pinholes, one in his heel and one in his elbow, and concluded he had brushed against the source while it was active. A momet's carelessness.