A couple of months ago, I forgot to put my phone into "silent mode" before playing my little once-a-month one-hour performance, and it rang while I was on stage (!!?!?).

A year or two ago I was watching Fairport Convention on stage when one of their phones went off on stage ... It was Dave Swarbrick ringing! We all - Fairport, Dave and the audience - has an inpromptu chat.