if you just want it to echo to the active window or msg (you'll have to change the code) then use something like:

Code:
alias DDayTimer {
  :ask user to enter date/time combination
  set %DDayTime $$?="Enter date in this format: dd/mm/yy hh:nn:ss (e.g. 28/03/03 14:30:00)"
  ;convert this combination to seconds
  set %DDayTime $ctime(%DDayTime)
  ;If the variable does not contain numbers, return an error
  if (%DDayTime !isnum) { echo -a You must specify a valid date/time combination(1) | halt }
  ;If user entered a date that hasd passed, return an error
  if ($calc(%DDayTime - $ctime) <= 0) { echo -a You must specify a valid date/time combination(2) | halt }
  .timerDDayTimer1 1 $calc(%DDayTime - $ctime) { echo -a BANG! It's $asctime(HH:nn:ss) on $asctime(dddd dd mmmm yyyy) | timerDDayTimer2 off }
  .timerDDayTimer2 0 5 echo -a it's $calc(%DDayTime - $ctime) seconds till $asctime(%DDayTime)
}


Haven't got time to go through it, sorry, just leaving work!

Not tested it either! - It's something to start you off anyway...

Hope it helps in some way!