Something

on *:TEXT:brb*:#: {
  inc %timer.away 1
  set %timeraway. [ $+ [ $nick ] ] %timer.away
  msg $chan 7,1 $+ $nick will be right back, reason: $$2-
  set %awayreason. [ $+ [ $nick ] ] $$2-
  set %away. [ $+ [ $nick ] ] 0
  timer $+ %timeraway. [ $+ [ $nick ] ] 9999 1 /inc %away. [ $+ [ $nick ] ] 1
}

on *:TEXT:Back:#: {
  timer $+ %timeraway. [ $+ [ $nick ] ] off
  var %awaymin. [ $+ [ $nick ] ] $calc($+(%away. [ $+ [ $nick ] ],/,60)) $+ Min(s)
  msg $chan 7,1 $+ $nick has returned from: %awayreason. [ $+ [ $nick ] ] 
  msg $chan 7,1You have been away for %awaymin. [ $+ [ $nick ] ] $+ .
  unset %away. [ $+ [ $nick ] ]
}