Whats the funniest prank you have ever done?

Question: Whats the funniest prank you have ever done?
- Keywords:
  joke,
  prank,
  quirky
Asked by suh9000 to Emma, Jimmy, Janet, Niall, Simon on 16 Mar 2013.
- Niall Crawford answered on 16 Mar 2013:
  
  I’ve not done too many, I used to love jumping out on people to scare them – most people don’t appreciate it.

Question: Whats the funniest prank you have ever done?