Got bitten by the stored voltage in the cable of a colour TV tripler that had been switched off for 12 hours - just the voltage due to the stored charge in the capacitance of the cable. Dunno what it was (15Kv?) but it threw me backwards across the workshop, my hand was numb and the arm didn't work from the elbow down for about 12 hours.
Not intending to do that again in a hurry.