This will open the second editbox on all channels and use that to display the number of users in that channel plus an activity indicator.

This is my first script and just the first version of it. I'll probably fine tune it.
EDIT: This is the second version, I made it server aware and fine tuned some things. Will keep this updated as I improve it.
EDIT: third version shows words per minute instead of a meaningless number. Also press F2 for an activity overview of all open channels.
EDIT: now channels that don't get any activity for a while are deleted from the activity list.

;ActivityMonitor by Tritonio

alias reduceactivity {
  var %i = 1
  while ($hget(activity, %i).item) {
    var %t = $calc($hget(activity, $v1) * %decay)
    hadd activity $v1 %t
    inc %i
  }
  var %i = 1
  while ($hget(activity, %i).item) {
    var %j = $v1
    var %t = $calc($wpm($hget(activity, $v1)))
    if (%t < 0.009) {
      hdel activity %j
      break
    }
    inc %i
  }
  showactivity $active $activecid
}

alias F2 {
  var %i = 1
  echo 7 -g -------------------------
  echo 7 -g Activity in open channels
  while ($hget(activity, %i).item) {
    var %a = $hget(activity,$v1)
    echo 7 -g $round($wpm(%a),2) wpm in $v1
    inc %i
  }
  echo 7 -g -------------------------
}

alias wpm {
  return $calc(($1 - $1 * %decay ^ 2)/(2 * %decay)*60)
}

alias showactivity {
  scid $2
  var %a = $hget(activity,$+($2,$1))
  editbox -oq1 $1 $1 $+ : $nick($1,0)   Activity: $round($wpm(%a),2) wpm
}

alias resetactivitytable {
  hfree activity
  hmake activity 15
}

on *:START:{
  hmake activity 15
  set -e %decay 0.995
  timer -io 0 1 /reduceactivity
}

on *:JOIN:#: {
  showactivity $chan $cid
}

on *:PART:#: {
  showactivity $chan $cid
}

on *:ACTIVE:#: {
  showactivity $active $activecid
}

on *:TEXT:*:#: {
  hadd activity $+($cid,$chan) $calc( $hget(activity, $+($cid,$chan) ) + $0)
}

on 1:INPUT:#: {
  if ($left($1,1) != / ) hadd activity $+($cid,$chan) $calc( $hget(activity, $+($cid,$chan) ) + $0)