Someone is disturbed while praying
Question

                If a person has something happen to him (i.e., someone speaks to him or 
approaches him) while praying what should he do?
Praise be to Allah.If it is a man, he should pronounce tasbeeh (glorifying 
  Allah by saying "subhan Allah"), and if it’s a woman, 
  she should clap. The evidence is Sahl Bin Saad’s narration that the Messenger 
   (peace and blessings of Allah be upon him) said, 
  "If something bothers you in your salaat, men should make tasbeeh 
  and women should clap."1
From the book What Should You Do in 
  the Following Situations... ?
1 Sunan Abu Dawood 941, 
  Sahih al-Bukhari (Bugha print) 1145, and Sahih Muslim 106.