Someone

on *:invite:#:{
  if ($me == [dev]runescript) {
    set $+(%,invite,.,#) $true
    join #
  }
}

on *:join:#:{
  if ($nick == $me) && ($me == [dev]runescript) && ($($+(%,invite,.,#),2)) {
    msg # hi! i was invited by $+($nick(#,$rand(1,$nick(#,0))),!)
    unset $($+(%,invite,.,#),1)
  }
}