Mine

on *:JOIN:#:{ 
  if (!%revolve. [ $+ [ $nick ] ]) { 
    set -u10 %revolve. [ $+ [ $nick ] ] 1 
  } 
  else { inc %revolve. [ $+ [ $nick ] ] } 
  if (%revolve. [ $+ [ $nick ] ] == 3) { 
    Ban # $nick staying or leaving :S (Hop FLood Ban) 
    unset %revolve. [ $+ [ $nick ] ] 
  } 
}