One examinee's cell phone went off during the writing portion at the very end. By that time everyone was so exhausted and apathetic that nobody seemed to really care.
On a related note: during an undergrad final exam, some dumbass had his phone go off and instead of immediately turning it off, he picked it up, looked at his phone to see who was calling him, smiled, then turned it off. Fortunately for him, assaulting a student during an exam would get you expelled.